Let's solve each of these pre-algebra equations step by step using
inverse operations. The goal is to isolate the variable $ y $ in each equation.
---
1. $ 3 + y \times 12 = 147 $
We need to isolate $ y $. First, subtract 3 from both sides:
$$
y \times 12 = 147 - 3 = 144
$$
Now divide both sides by 12:
$$
y = \frac{144}{12} = 12
$$
✔ Answer: $ y = 12 $
---
2. $ 8 \times y + y = 117 $
Combine like terms on the left:
$$
(8y + y) = 9y
$$
So:
$$
9y = 117
$$
Divide both sides by 9:
$$
y = \frac{117}{9} = 13
$$
✔ Answer: $ y = 13 $
---
3. $ 11^2 - 12 \times y = -47 $
First, compute $ 11^2 = 121 $
$$
121 - 12y = -47
$$
Subtract 121 from both sides:
$$
-12y = -47 - 121 = -168
$$
Divide both sides by -12:
$$
y = \frac{-168}{-12} = 14
$$
✔ Answer: $ y = 14 $
---
4. $ 10^2 - 12 \times y = 52 $
$ 10^2 = 100 $
$$
100 - 12y = 52
$$
Subtract 100 from both sides:
$$
-12y = 52 - 100 = -48
$$
Divide by -12:
$$
y = \frac{-48}{-12} = 4
$$
✔ Answer: $ y = 4 $
---
5. $ 11^2 - 10 \times y = -19 $
$ 11^2 = 121 $
$$
121 - 10y = -19
$$
Subtract 121:
$$
-10y = -19 - 121 = -140
$$
Divide by -10:
$$
y = \frac{-140}{-10} = 14
$$
✔ Answer: $ y = 14 $
---
6. $ 5 + 10 \times y = 155 $
Subtract 5 from both sides:
$$
10y = 155 - 5 = 150
$$
Divide by 10:
$$
y = \frac{150}{10} = 15
$$
✔ Answer: $ y = 15 $
---
7. $ 1^2 + y \times 10 = 151 $
$ 1^2 = 1 $
$$
1 + 10y = 151
$$
Subtract 1:
$$
10y = 150
$$
Divide by 10:
$$
y = 15
$$
✔ Answer: $ y = 15 $
---
8. $ 9 \times y + y = 60 $
Combine like terms:
$$
9y + y = 10y
$$
$$
10y = 60
$$
Divide by 10:
$$
y = 6
$$
✔ Answer: $ y = 6 $
---
9. $ 14 \times y + 14 = 224 $
Subtract 14 from both sides:
$$
14y = 224 - 14 = 210
$$
Divide by 14:
$$
y = \frac{210}{14} = 15
$$
✔ Answer: $ y = 15 $
---
10. $ 12^2 + y \times 10 = 164 $
$ 12^2 = 144 $
$$
144 + 10y = 164
$$
Subtract 144:
$$
10y = 164 - 144 = 20
$$
Divide by 10:
$$
y = \frac{20}{10} = 2
$$
✔ Answer: $ y = 2 $
---
✔ Final Answers:
1. $ y = 12 $
2. $ y = 13 $
3. $ y = 14 $
4. $ y = 4 $
5. $ y = 14 $
6. $ y = 15 $
7. $ y = 15 $
8. $ y = 6 $
9. $ y = 15 $
10. $ y = 2 $
Let me know if you'd like these steps written out in a worksheet format!
Parent Tip: Review the logic above to help your child master the concept of solving algebraic equations worksheets.