Precalculus - Fractions Worksheet - Free Printable
Educational worksheet: Precalculus - Fractions Worksheet. Download and print for classroom or home learning activities.
JPG
495×640
24.8 KB
Free · Personal Use
Quality Assured by Worksheets Library Team
Reviewed for educational accuracy and age-appropriateness
ID: #1313899
⭐
Show Answer Key & Explanations
Step-by-step solution for: Precalculus - Fractions Worksheet
▼
Show Answer Key & Explanations
Step-by-step solution for: Precalculus - Fractions Worksheet
Let's solve each problem step by step from the Precalculus Fractions Worksheet. We'll evaluate and simplify expressions involving fractions, integers, and algebraic terms.
---
We will evaluate each expression using fraction arithmetic rules (common denominators, signs, etc.).
---
#### 1) $\left(-\frac{1}{6}\right) - \frac{2}{5}$
Find a common denominator: $30$
$$
= \left(-\frac{5}{30}\right) - \frac{12}{30} = -\frac{17}{30}
$$
✔ Answer: $-\frac{17}{30}$
---
#### 2) $(-2\frac{1}{2}) + 2\frac{2}{3}$
Convert to improper fractions:
- $-2\frac{1}{2} = -\frac{5}{2}$
- $2\frac{2}{3} = \frac{8}{3}$
Common denominator: 6
$$
= -\frac{15}{6} + \frac{16}{6} = \frac{1}{6}
$$
✔ Answer: $\frac{1}{6}$
---
#### 3) $\left(-\frac{1}{4}\right) - 1\frac{1}{3}$
Convert mixed number: $1\frac{1}{3} = \frac{4}{3}$
So:
$$
= -\frac{1}{4} - \frac{4}{3}
$$
Common denominator: 12
$$
= -\frac{3}{12} - \frac{16}{12} = -\frac{19}{12}
$$
✔ Answer: $-\frac{19}{12}$ or $-1\frac{7}{12}$
---
#### 4) $\left(-\frac{1}{4}\right) - \left(-\frac{3}{8}\right)$
Subtracting a negative is adding:
$$
= -\frac{1}{4} + \frac{3}{8}
$$
Common denominator: 8
$$
= -\frac{2}{8} + \frac{3}{8} = \frac{1}{8}
$$
✔ Answer: $\frac{1}{8}$
---
#### 5) $\frac{13}{8} - 1\frac{1}{3}$
Convert $1\frac{1}{3} = \frac{4}{3}$
Common denominator: 24
$$
\frac{13}{8} = \frac{39}{24},\quad \frac{4}{3} = \frac{32}{24}
$$
$$
= \frac{39}{24} - \frac{32}{24} = \frac{7}{24}
$$
✔ Answer: $\frac{7}{24}$
---
#### 6) $\left(-\frac{1}{2}\right) + \left(-\frac{7}{8}\right)$
Add negatives:
$$
= -\frac{1}{2} - \frac{7}{8} = -\frac{4}{8} - \frac{7}{8} = -\frac{11}{8}
$$
✔ Answer: $-\frac{11}{8}$ or $-1\frac{3}{8}$
---
#### 7) $\frac{5}{7} + \left(-\frac{9}{5}\right)$
$$
= \frac{5}{7} - \frac{9}{5}
$$
Common denominator: 35
$$
= \frac{25}{35} - \frac{63}{35} = -\frac{38}{35}
$$
✔ Answer: $-\frac{38}{35}$ or $-1\frac{3}{35}$
---
#### 8) $(-2) + 3\frac{1}{2}$
$3\frac{1}{2} = \frac{7}{2}$
$$
-2 + \frac{7}{2} = -\frac{4}{2} + \frac{7}{2} = \frac{3}{2}
$$
✔ Answer: $\frac{3}{2}$ or $1\frac{1}{2}$
---
#### 9) $(-2) - \frac{3}{2}$
$$
= -2 - 1.5 = -3.5 = -\frac{7}{2}
$$
Or:
$$
= -\frac{4}{2} - \frac{3}{2} = -\frac{7}{2}
$$
✔ Answer: $-\frac{7}{2}$ or $-3\frac{1}{2}$
---
#### 10) $(-1) - \left(-3\frac{1}{4}\right)$
$-3\frac{1}{4} = -\frac{13}{4}$
So:
$$
-1 - (-\frac{13}{4}) = -1 + \frac{13}{4} = -\frac{4}{4} + \frac{13}{4} = \frac{9}{4}
$$
✔ Answer: $\frac{9}{4}$ or $2\frac{1}{4}$
---
#### 11) $\left(-\frac{2}{8}\right) + 3\frac{1}{2} - \frac{3}{4}$
Simplify $-\frac{2}{8} = -\frac{1}{4}$
$3\frac{1}{2} = \frac{7}{2}$
Now:
$$
= -\frac{1}{4} + \frac{7}{2} - \frac{3}{4}
$$
Common denominator: 4
$$
= -\frac{1}{4} + \frac{14}{4} - \frac{3}{4} = \frac{10}{4} = \frac{5}{2}
$$
✔ Answer: $\frac{5}{2}$ or $2\frac{1}{2}$
---
#### 12) $\frac{3}{4} - \frac{7}{6} - 2$
Convert all to common denominator: 12
$$
\frac{3}{4} = \frac{9}{12},\quad \frac{7}{6} = \frac{14}{12},\quad 2 = \frac{24}{12}
$$
$$
= \frac{9}{12} - \frac{14}{12} - \frac{24}{12} = \frac{-29}{12}
$$
✔ Answer: $-\frac{29}{12}$ or $-2\frac{5}{12}$
---
#### 13) $\left(-\frac{3}{4}\right) + \frac{2}{3} + 3 - 1\frac{5}{7}$
Convert all to improper fractions:
- $3 = \frac{3}{1}$
- $1\frac{5}{7} = \frac{12}{7}$
Now:
$$
= -\frac{3}{4} + \frac{2}{3} + \frac{3}{1} - \frac{12}{7}
$$
Find LCD of 4, 3, 1, 7 → LCM(4,3,7) = 84
Convert:
- $-\frac{3}{4} = -\frac{63}{84}$
- $\frac{2}{3} = \frac{56}{84}$
- $\frac{3}{1} = \frac{252}{84}$
- $-\frac{12}{7} = -\frac{144}{84}$
Now add:
$$
-63 + 56 + 252 - 144 = (-63 + 56) = -7,\quad (-7 + 252) = 245,\quad (245 - 144) = 101
$$
So: $\frac{101}{84}$
✔ Answer: $\frac{101}{84}$ or $1\frac{17}{84}$
---
#### 14) $\left(-\frac{3}{2}\right) - 4\left(-2\right) - 4\frac{2}{3}$
First, compute $-4(-2) = +8$
Then $4\frac{2}{3} = \frac{14}{3}$
So:
$$
= -\frac{3}{2} + 8 - \frac{14}{3}
$$
Convert to common denominator: 6
- $-\frac{3}{2} = -\frac{9}{6}$
- $8 = \frac{48}{6}$
- $-\frac{14}{3} = -\frac{28}{6}$
Now:
$$
-\frac{9}{6} + \frac{48}{6} - \frac{28}{6} = \frac{11}{6}
$$
✔ Answer: $\frac{11}{6}$ or $1\frac{5}{6}$
---
#### 15) $1 + \frac{9}{5} + 3\frac{1}{6} + \left(-3\frac{1}{2}\right)$
Convert all:
- $3\frac{1}{6} = \frac{19}{6}$
- $-3\frac{1}{2} = -\frac{7}{2}$
Now:
$$
1 + \frac{9}{5} + \frac{19}{6} - \frac{7}{2}
$$
LCD of 5,6,2 = 30
Convert:
- $1 = \frac{30}{30}$
- $\frac{9}{5} = \frac{54}{30}$
- $\frac{19}{6} = \frac{95}{30}$
- $-\frac{7}{2} = -\frac{105}{30}$
Add:
$$
30 + 54 + 95 - 105 = 74
$$
So: $\frac{74}{30} = \frac{37}{15}$
✔ Answer: $\frac{37}{15}$ or $2\frac{7}{15}$
---
#### 16) $\left(-\frac{2}{3}\right) - \left(-\frac{1}{3}\right) + 2 - \left(-\frac{9}{7}\right)$
Simplify:
- $-\frac{2}{3} + \frac{1}{3} = -\frac{1}{3}$
- Then $+2$
- Then $+ \frac{9}{7}$
So:
$$
-\frac{1}{3} + 2 + \frac{9}{7}
$$
Convert:
- $2 = \frac{42}{21}$, better LCD of 3 and 7 is 21
- $-\frac{1}{3} = -\frac{7}{21}$
- $2 = \frac{42}{21}$
- $\frac{9}{7} = \frac{27}{21}$
Add:
$$
-7 + 42 + 27 = 62 → \frac{62}{21}
$$
✔ Answer: $\frac{62}{21}$ or $2\frac{20}{21}$
---
Now we simplify algebraic expressions with fractions.
---
#### 17) $\left(-\frac{3}{2}x - 1\right) + \left(-\frac{5}{3}x^2 + \frac{4}{3}\right)$
Group like terms:
- $-\frac{5}{3}x^2$
- $-\frac{3}{2}x$
- $-1 + \frac{4}{3} = \frac{-3}{3} + \frac{4}{3} = \frac{1}{3}$
So:
$$
-\frac{5}{3}x^2 - \frac{3}{2}x + \frac{1}{3}
$$
✔ Answer: $-\frac{5}{3}x^2 - \frac{3}{2}x + \frac{1}{3}$
---
#### 18) $\left(\frac{14}{3}x - \frac{1}{2}\right) + \left(\frac{7}{2}x + \frac{4}{3}x^2\right)$
Group:
- $\frac{4}{3}x^2$
- $\frac{14}{3}x + \frac{7}{2}x$
- $-\frac{1}{2}$
First, combine $x$ terms:
LCD of 3 and 2 is 6:
- $\frac{14}{3}x = \frac{28}{6}x$
- $\frac{7}{2}x = \frac{21}{6}x$
- Sum: $\frac{49}{6}x$
Constant: $-\frac{1}{2}$
So:
$$
\frac{4}{3}x^2 + \frac{49}{6}x - \frac{1}{2}
$$
✔ Answer: $\frac{4}{3}x^2 + \frac{49}{6}x - \frac{1}{2}$
---
#### 19) $\left(\frac{12}{6}x^3 + \frac{2}{3}\right) + \left(\frac{7}{2} + \frac{5}{2}x^3\right)$
Simplify $\frac{12}{6}x^3 = 2x^3$
Now:
- $2x^3 + \frac{5}{2}x^3 = \left(2 + \frac{5}{2}\right)x^3 = \frac{4}{2} + \frac{5}{2} = \frac{9}{2}x^3$
- Constants: $\frac{2}{3} + \frac{7}{2}$
LCD of 3 and 2 is 6:
- $\frac{2}{3} = \frac{4}{6},\quad \frac{7}{2} = \frac{21}{6} → \frac{25}{6}$
So:
$$
\frac{9}{2}x^3 + \frac{25}{6}
$$
✔ Answer: $\frac{9}{2}x^3 + \frac{25}{6}$
---
#### 20) $\left(\frac{19}{5}x^3 + 2x^2\right) - \left(\frac{2}{3}x^3 - \frac{25}{8}x\right)$
Distribute the minus sign:
$$
= \frac{19}{5}x^3 + 2x^2 - \frac{2}{3}x^3 + \frac{25}{8}x
$$
Combine like terms:
- $x^3$: $\frac{19}{5} - \frac{2}{3}$
LCD = 15:
- $\frac{19}{5} = \frac{57}{15},\quad \frac{2}{3} = \frac{10}{15} → \frac{47}{15}x^3$
- $x^2$: $2x^2$
- $x$: $\frac{25}{8}x$
No constant.
So:
$$
\frac{47}{15}x^3 + 2x^2 + \frac{25}{8}x
$$
✔ Answer: $\frac{47}{15}x^3 + 2x^2 + \frac{25}{8}x$
---
#### 21) $\left(-\frac{5}{3}x + \frac{5}{4}x^2\right) + \left(\frac{1}{4}x^2 - 2x^3\right)$
Group:
- $x^3$: $-2x^3$
- $x^2$: $\frac{5}{4}x^2 + \frac{1}{4}x^2 = \frac{6}{4}x^2 = \frac{3}{2}x^2$
- $x$: $-\frac{5}{3}x$
So:
$$
-2x^3 + \frac{3}{2}x^2 - \frac{5}{3}x
$$
✔ Answer: $-2x^3 + \frac{3}{2}x^2 - \frac{5}{3}x$
---
#### 22) $\left(-\frac{10}{7}x^3 - \frac{4}{3}\right) + \left(\frac{29}{6} + \frac{1}{5}x^3\right)$
Group:
- $x^3$: $-\frac{10}{7}x^3 + \frac{1}{5}x^3$
LCD of 7 and 5 = 35
- $-\frac{10}{7} = -\frac{50}{35},\quad \frac{1}{5} = \frac{7}{35} → -\frac{43}{35}x^3$
Constants: $-\frac{4}{3} + \frac{29}{6}$
LCD of 3 and 6 = 6
- $-\frac{4}{3} = -\frac{8}{6},\quad \frac{29}{6} → \frac{21}{6} = \frac{7}{2}$
So:
$$
-\frac{43}{35}x^3 + \frac{7}{2}
$$
✔ Answer: $-\frac{43}{35}x^3 + \frac{7}{2}$
---
| Problem | Answer |
|--------|--------|
| 1 | $-\frac{17}{30}$ |
| 2 | $\frac{1}{6}$ |
| 3 | $-\frac{19}{12}$ |
| 4 | $\frac{1}{8}$ |
| 5 | $\frac{7}{24}$ |
| 6 | $-\frac{11}{8}$ |
| 7 | $-\frac{38}{35}$ |
| 8 | $\frac{3}{2}$ |
| 9 | $-\frac{7}{2}$ |
| 10 | $\frac{9}{4}$ |
| 11 | $\frac{5}{2}$ |
| 12 | $-\frac{29}{12}$ |
| 13 | $\frac{101}{84}$ |
| 14 | $\frac{11}{6}$ |
| 15 | $\frac{37}{15}$ |
| 16 | $\frac{62}{21}$ |
| 17 | $-\frac{5}{3}x^2 - \frac{3}{2}x + \frac{1}{3}$ |
| 18 | $\frac{4}{3}x^2 + \frac{49}{6}x - \frac{1}{2}$ |
| 19 | $\frac{9}{2}x^3 + \frac{25}{6}$ |
| 20 | $\frac{47}{15}x^3 + 2x^2 + \frac{25}{8}x$ |
| 21 | $-2x^3 + \frac{3}{2}x^2 - \frac{5}{3}x$ |
| 22 | $-\frac{43}{35}x^3 + \frac{7}{2}$ |
Let me know if you'd like these boxed or formatted differently!
---
Part 1: Evaluate Each Expression
We will evaluate each expression using fraction arithmetic rules (common denominators, signs, etc.).
---
#### 1) $\left(-\frac{1}{6}\right) - \frac{2}{5}$
Find a common denominator: $30$
$$
= \left(-\frac{5}{30}\right) - \frac{12}{30} = -\frac{17}{30}
$$
✔ Answer: $-\frac{17}{30}$
---
#### 2) $(-2\frac{1}{2}) + 2\frac{2}{3}$
Convert to improper fractions:
- $-2\frac{1}{2} = -\frac{5}{2}$
- $2\frac{2}{3} = \frac{8}{3}$
Common denominator: 6
$$
= -\frac{15}{6} + \frac{16}{6} = \frac{1}{6}
$$
✔ Answer: $\frac{1}{6}$
---
#### 3) $\left(-\frac{1}{4}\right) - 1\frac{1}{3}$
Convert mixed number: $1\frac{1}{3} = \frac{4}{3}$
So:
$$
= -\frac{1}{4} - \frac{4}{3}
$$
Common denominator: 12
$$
= -\frac{3}{12} - \frac{16}{12} = -\frac{19}{12}
$$
✔ Answer: $-\frac{19}{12}$ or $-1\frac{7}{12}$
---
#### 4) $\left(-\frac{1}{4}\right) - \left(-\frac{3}{8}\right)$
Subtracting a negative is adding:
$$
= -\frac{1}{4} + \frac{3}{8}
$$
Common denominator: 8
$$
= -\frac{2}{8} + \frac{3}{8} = \frac{1}{8}
$$
✔ Answer: $\frac{1}{8}$
---
#### 5) $\frac{13}{8} - 1\frac{1}{3}$
Convert $1\frac{1}{3} = \frac{4}{3}$
Common denominator: 24
$$
\frac{13}{8} = \frac{39}{24},\quad \frac{4}{3} = \frac{32}{24}
$$
$$
= \frac{39}{24} - \frac{32}{24} = \frac{7}{24}
$$
✔ Answer: $\frac{7}{24}$
---
#### 6) $\left(-\frac{1}{2}\right) + \left(-\frac{7}{8}\right)$
Add negatives:
$$
= -\frac{1}{2} - \frac{7}{8} = -\frac{4}{8} - \frac{7}{8} = -\frac{11}{8}
$$
✔ Answer: $-\frac{11}{8}$ or $-1\frac{3}{8}$
---
#### 7) $\frac{5}{7} + \left(-\frac{9}{5}\right)$
$$
= \frac{5}{7} - \frac{9}{5}
$$
Common denominator: 35
$$
= \frac{25}{35} - \frac{63}{35} = -\frac{38}{35}
$$
✔ Answer: $-\frac{38}{35}$ or $-1\frac{3}{35}$
---
#### 8) $(-2) + 3\frac{1}{2}$
$3\frac{1}{2} = \frac{7}{2}$
$$
-2 + \frac{7}{2} = -\frac{4}{2} + \frac{7}{2} = \frac{3}{2}
$$
✔ Answer: $\frac{3}{2}$ or $1\frac{1}{2}$
---
#### 9) $(-2) - \frac{3}{2}$
$$
= -2 - 1.5 = -3.5 = -\frac{7}{2}
$$
Or:
$$
= -\frac{4}{2} - \frac{3}{2} = -\frac{7}{2}
$$
✔ Answer: $-\frac{7}{2}$ or $-3\frac{1}{2}$
---
#### 10) $(-1) - \left(-3\frac{1}{4}\right)$
$-3\frac{1}{4} = -\frac{13}{4}$
So:
$$
-1 - (-\frac{13}{4}) = -1 + \frac{13}{4} = -\frac{4}{4} + \frac{13}{4} = \frac{9}{4}
$$
✔ Answer: $\frac{9}{4}$ or $2\frac{1}{4}$
---
#### 11) $\left(-\frac{2}{8}\right) + 3\frac{1}{2} - \frac{3}{4}$
Simplify $-\frac{2}{8} = -\frac{1}{4}$
$3\frac{1}{2} = \frac{7}{2}$
Now:
$$
= -\frac{1}{4} + \frac{7}{2} - \frac{3}{4}
$$
Common denominator: 4
$$
= -\frac{1}{4} + \frac{14}{4} - \frac{3}{4} = \frac{10}{4} = \frac{5}{2}
$$
✔ Answer: $\frac{5}{2}$ or $2\frac{1}{2}$
---
#### 12) $\frac{3}{4} - \frac{7}{6} - 2$
Convert all to common denominator: 12
$$
\frac{3}{4} = \frac{9}{12},\quad \frac{7}{6} = \frac{14}{12},\quad 2 = \frac{24}{12}
$$
$$
= \frac{9}{12} - \frac{14}{12} - \frac{24}{12} = \frac{-29}{12}
$$
✔ Answer: $-\frac{29}{12}$ or $-2\frac{5}{12}$
---
#### 13) $\left(-\frac{3}{4}\right) + \frac{2}{3} + 3 - 1\frac{5}{7}$
Convert all to improper fractions:
- $3 = \frac{3}{1}$
- $1\frac{5}{7} = \frac{12}{7}$
Now:
$$
= -\frac{3}{4} + \frac{2}{3} + \frac{3}{1} - \frac{12}{7}
$$
Find LCD of 4, 3, 1, 7 → LCM(4,3,7) = 84
Convert:
- $-\frac{3}{4} = -\frac{63}{84}$
- $\frac{2}{3} = \frac{56}{84}$
- $\frac{3}{1} = \frac{252}{84}$
- $-\frac{12}{7} = -\frac{144}{84}$
Now add:
$$
-63 + 56 + 252 - 144 = (-63 + 56) = -7,\quad (-7 + 252) = 245,\quad (245 - 144) = 101
$$
So: $\frac{101}{84}$
✔ Answer: $\frac{101}{84}$ or $1\frac{17}{84}$
---
#### 14) $\left(-\frac{3}{2}\right) - 4\left(-2\right) - 4\frac{2}{3}$
First, compute $-4(-2) = +8$
Then $4\frac{2}{3} = \frac{14}{3}$
So:
$$
= -\frac{3}{2} + 8 - \frac{14}{3}
$$
Convert to common denominator: 6
- $-\frac{3}{2} = -\frac{9}{6}$
- $8 = \frac{48}{6}$
- $-\frac{14}{3} = -\frac{28}{6}$
Now:
$$
-\frac{9}{6} + \frac{48}{6} - \frac{28}{6} = \frac{11}{6}
$$
✔ Answer: $\frac{11}{6}$ or $1\frac{5}{6}$
---
#### 15) $1 + \frac{9}{5} + 3\frac{1}{6} + \left(-3\frac{1}{2}\right)$
Convert all:
- $3\frac{1}{6} = \frac{19}{6}$
- $-3\frac{1}{2} = -\frac{7}{2}$
Now:
$$
1 + \frac{9}{5} + \frac{19}{6} - \frac{7}{2}
$$
LCD of 5,6,2 = 30
Convert:
- $1 = \frac{30}{30}$
- $\frac{9}{5} = \frac{54}{30}$
- $\frac{19}{6} = \frac{95}{30}$
- $-\frac{7}{2} = -\frac{105}{30}$
Add:
$$
30 + 54 + 95 - 105 = 74
$$
So: $\frac{74}{30} = \frac{37}{15}$
✔ Answer: $\frac{37}{15}$ or $2\frac{7}{15}$
---
#### 16) $\left(-\frac{2}{3}\right) - \left(-\frac{1}{3}\right) + 2 - \left(-\frac{9}{7}\right)$
Simplify:
- $-\frac{2}{3} + \frac{1}{3} = -\frac{1}{3}$
- Then $+2$
- Then $+ \frac{9}{7}$
So:
$$
-\frac{1}{3} + 2 + \frac{9}{7}
$$
Convert:
- $2 = \frac{42}{21}$, better LCD of 3 and 7 is 21
- $-\frac{1}{3} = -\frac{7}{21}$
- $2 = \frac{42}{21}$
- $\frac{9}{7} = \frac{27}{21}$
Add:
$$
-7 + 42 + 27 = 62 → \frac{62}{21}
$$
✔ Answer: $\frac{62}{21}$ or $2\frac{20}{21}$
---
Part 2: Simplify Each Expression
Now we simplify algebraic expressions with fractions.
---
#### 17) $\left(-\frac{3}{2}x - 1\right) + \left(-\frac{5}{3}x^2 + \frac{4}{3}\right)$
Group like terms:
- $-\frac{5}{3}x^2$
- $-\frac{3}{2}x$
- $-1 + \frac{4}{3} = \frac{-3}{3} + \frac{4}{3} = \frac{1}{3}$
So:
$$
-\frac{5}{3}x^2 - \frac{3}{2}x + \frac{1}{3}
$$
✔ Answer: $-\frac{5}{3}x^2 - \frac{3}{2}x + \frac{1}{3}$
---
#### 18) $\left(\frac{14}{3}x - \frac{1}{2}\right) + \left(\frac{7}{2}x + \frac{4}{3}x^2\right)$
Group:
- $\frac{4}{3}x^2$
- $\frac{14}{3}x + \frac{7}{2}x$
- $-\frac{1}{2}$
First, combine $x$ terms:
LCD of 3 and 2 is 6:
- $\frac{14}{3}x = \frac{28}{6}x$
- $\frac{7}{2}x = \frac{21}{6}x$
- Sum: $\frac{49}{6}x$
Constant: $-\frac{1}{2}$
So:
$$
\frac{4}{3}x^2 + \frac{49}{6}x - \frac{1}{2}
$$
✔ Answer: $\frac{4}{3}x^2 + \frac{49}{6}x - \frac{1}{2}$
---
#### 19) $\left(\frac{12}{6}x^3 + \frac{2}{3}\right) + \left(\frac{7}{2} + \frac{5}{2}x^3\right)$
Simplify $\frac{12}{6}x^3 = 2x^3$
Now:
- $2x^3 + \frac{5}{2}x^3 = \left(2 + \frac{5}{2}\right)x^3 = \frac{4}{2} + \frac{5}{2} = \frac{9}{2}x^3$
- Constants: $\frac{2}{3} + \frac{7}{2}$
LCD of 3 and 2 is 6:
- $\frac{2}{3} = \frac{4}{6},\quad \frac{7}{2} = \frac{21}{6} → \frac{25}{6}$
So:
$$
\frac{9}{2}x^3 + \frac{25}{6}
$$
✔ Answer: $\frac{9}{2}x^3 + \frac{25}{6}$
---
#### 20) $\left(\frac{19}{5}x^3 + 2x^2\right) - \left(\frac{2}{3}x^3 - \frac{25}{8}x\right)$
Distribute the minus sign:
$$
= \frac{19}{5}x^3 + 2x^2 - \frac{2}{3}x^3 + \frac{25}{8}x
$$
Combine like terms:
- $x^3$: $\frac{19}{5} - \frac{2}{3}$
LCD = 15:
- $\frac{19}{5} = \frac{57}{15},\quad \frac{2}{3} = \frac{10}{15} → \frac{47}{15}x^3$
- $x^2$: $2x^2$
- $x$: $\frac{25}{8}x$
No constant.
So:
$$
\frac{47}{15}x^3 + 2x^2 + \frac{25}{8}x
$$
✔ Answer: $\frac{47}{15}x^3 + 2x^2 + \frac{25}{8}x$
---
#### 21) $\left(-\frac{5}{3}x + \frac{5}{4}x^2\right) + \left(\frac{1}{4}x^2 - 2x^3\right)$
Group:
- $x^3$: $-2x^3$
- $x^2$: $\frac{5}{4}x^2 + \frac{1}{4}x^2 = \frac{6}{4}x^2 = \frac{3}{2}x^2$
- $x$: $-\frac{5}{3}x$
So:
$$
-2x^3 + \frac{3}{2}x^2 - \frac{5}{3}x
$$
✔ Answer: $-2x^3 + \frac{3}{2}x^2 - \frac{5}{3}x$
---
#### 22) $\left(-\frac{10}{7}x^3 - \frac{4}{3}\right) + \left(\frac{29}{6} + \frac{1}{5}x^3\right)$
Group:
- $x^3$: $-\frac{10}{7}x^3 + \frac{1}{5}x^3$
LCD of 7 and 5 = 35
- $-\frac{10}{7} = -\frac{50}{35},\quad \frac{1}{5} = \frac{7}{35} → -\frac{43}{35}x^3$
Constants: $-\frac{4}{3} + \frac{29}{6}$
LCD of 3 and 6 = 6
- $-\frac{4}{3} = -\frac{8}{6},\quad \frac{29}{6} → \frac{21}{6} = \frac{7}{2}$
So:
$$
-\frac{43}{35}x^3 + \frac{7}{2}
$$
✔ Answer: $-\frac{43}{35}x^3 + \frac{7}{2}$
---
✔ Final Answers Summary
| Problem | Answer |
|--------|--------|
| 1 | $-\frac{17}{30}$ |
| 2 | $\frac{1}{6}$ |
| 3 | $-\frac{19}{12}$ |
| 4 | $\frac{1}{8}$ |
| 5 | $\frac{7}{24}$ |
| 6 | $-\frac{11}{8}$ |
| 7 | $-\frac{38}{35}$ |
| 8 | $\frac{3}{2}$ |
| 9 | $-\frac{7}{2}$ |
| 10 | $\frac{9}{4}$ |
| 11 | $\frac{5}{2}$ |
| 12 | $-\frac{29}{12}$ |
| 13 | $\frac{101}{84}$ |
| 14 | $\frac{11}{6}$ |
| 15 | $\frac{37}{15}$ |
| 16 | $\frac{62}{21}$ |
| 17 | $-\frac{5}{3}x^2 - \frac{3}{2}x + \frac{1}{3}$ |
| 18 | $\frac{4}{3}x^2 + \frac{49}{6}x - \frac{1}{2}$ |
| 19 | $\frac{9}{2}x^3 + \frac{25}{6}$ |
| 20 | $\frac{47}{15}x^3 + 2x^2 + \frac{25}{8}x$ |
| 21 | $-2x^3 + \frac{3}{2}x^2 - \frac{5}{3}x$ |
| 22 | $-\frac{43}{35}x^3 + \frac{7}{2}$ |
Let me know if you'd like these boxed or formatted differently!
Parent Tip: Review the logic above to help your child master the concept of pre calculus worksheet.