Absolute Value Equations Worksheet for 9th - 11th Grade | Lesson ... - Free Printable
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Step-by-step solution for: Absolute Value Equations Worksheet for 9th - 11th Grade | Lesson ...
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Show Answer Key & Explanations
Step-by-step solution for: Absolute Value Equations Worksheet for 9th - 11th Grade | Lesson ...
Let’s solve each absolute value equation one by one. Remember:
Absolute value means distance from zero — so it’s always positive or zero.
If |x| = a, then x = a or x = -a (as long as a ≥ 0).
If the right side is negative, there’s no solution, because absolute value can’t be negative.
---
We’ll go problem by problem:
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(1) |3x + 4| = 42
Set up two equations:
- 3x + 4 = 42 → 3x = 38 → x = 38/3
- 3x + 4 = -42 → 3x = -46 → x = -46/3
✔ Solutions: x = 38/3, x = -46/3
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(2) |-4x| = 20
This is same as |4x| = 20 (since |-4x| = |4x|)
So:
- 4x = 20 → x = 5
- 4x = -20 → x = -5
✔ Solutions: x = 5, x = -5
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(3) |x - 10| + 7 = 7
Subtract 7 from both sides:
|x - 10| = 0
Only one solution when absolute value equals 0:
x - 10 = 0 → x = 10
✔ Solution: x = 10
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(4) |(1/2)x| = 3
Multiply both sides by 2 to eliminate fraction? Or just solve directly:
(1/2)x = 3 → x = 6
(1/2)x = -3 → x = -6
✔ Solutions: x = 6, x = -6
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(5) |7 + x| = -1
Wait! Absolute value cannot equal a negative number.
✘ No solution
---
(6) |-2x| = 19
Same as |2x| = 19
So:
2x = 19 → x = 19/2
2x = -19 → x = -19/2
✔ Solutions: x = 19/2, x = -19/2
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(7) 5|x| = 30
Divide both sides by 5:
|x| = 6
So:
x = 6 or x = -6
✔ Solutions: x = 6, x = -6
---
(8) |(1/4)x| = 3
Multiply both sides by 4:
|x| = 12
So:
x = 12 or x = -12
✔ Solutions: x = 12, x = -12
---
(9) -5|x| = -12
Divide both sides by -5:
|x| = 12/5
So:
x = 12/5 or x = -12/5
✔ Solutions: x = 12/5, x = -12/5
---
(10) |4x| = 11
So:
4x = 11 → x = 11/4
4x = -11 → x = -11/4
✔ Solutions: x = 11/4, x = -11/4
---
(11) |x| - 3 = 2
Add 3 to both sides:
|x| = 5
So:
x = 5 or x = -5
✔ Solutions: x = 5, x = -5
---
(12) |(x/2)| = 5
Multiply both sides by 2:
|x| = 10
So:
x = 10 or x = -10
✔ Solutions: x = 10, x = -10
---
(13) |(2(x+1))/3| = 5
First, multiply both sides by 3:
|2(x+1)| = 15
Now divide both sides by 2? Or keep inside:
2(x+1) = 15 → x+1 = 15/2 → x = 15/2 - 1 = 13/2
OR
2(x+1) = -15 → x+1 = -15/2 → x = -15/2 - 1 = -17/2
✔ Solutions: x = 13/2, x = -17/2
---
(14) 4|x + 4| = 56
Divide both sides by 4:
|x + 4| = 14
So:
x + 4 = 14 → x = 10
x + 4 = -14 → x = -18
✔ Solutions: x = 10, x = -18
---
(15) |7x| - 3 = 73
Add 3 to both sides:
|7x| = 76
So:
7x = 76 → x = 76/7
7x = -76 → x = -76/7
✔ Solutions: x = 76/7, x = -76/7
---
(16) |(1/2)x - 4| = 7
Set up two cases:
Case 1: (1/2)x - 4 = 7 → (1/2)x = 11 → x = 22
Case 2: (1/2)x - 4 = -7 → (1/2)x = -3 → x = -6
✔ Solutions: x = 22, x = -6
---
(17) |(x+4)/4| = 3
Multiply both sides by 4:
|x + 4| = 12
So:
x + 4 = 12 → x = 8
x + 4 = -12 → x = -16
✔ Solutions: x = 8, x = -16
---
(18) -6|6x + 2| = -78
Divide both sides by -6:
|6x + 2| = 13
Now:
6x + 2 = 13 → 6x = 11 → x = 11/6
6x + 2 = -13 → 6x = -15 → x = -15/6 = -5/2
✔ Solutions: x = 11/6, x = -5/2
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Final Answer:
(1) x = 38/3, x = -46/3
(2) x = 5, x = -5
(3) x = 10
(4) x = 6, x = -6
(5) No solution
(6) x = 19/2, x = -19/2
(7) x = 6, x = -6
(8) x = 12, x = -12
(9) x = 12/5, x = -12/5
(10) x = 11/4, x = -11/4
(11) x = 5, x = -5
(12) x = 10, x = -10
(13) x = 13/2, x = -17/2
(14) x = 10, x = -18
(15) x = 76/7, x = -76/7
(16) x = 22, x = -6
(17) x = 8, x = -16
(18) x = 11/6, x = -5/2
Absolute value means distance from zero — so it’s always positive or zero.
If |x| = a, then x = a or x = -a (as long as a ≥ 0).
If the right side is negative, there’s no solution, because absolute value can’t be negative.
---
We’ll go problem by problem:
---
(1) |3x + 4| = 42
Set up two equations:
- 3x + 4 = 42 → 3x = 38 → x = 38/3
- 3x + 4 = -42 → 3x = -46 → x = -46/3
✔ Solutions: x = 38/3, x = -46/3
---
(2) |-4x| = 20
This is same as |4x| = 20 (since |-4x| = |4x|)
So:
- 4x = 20 → x = 5
- 4x = -20 → x = -5
✔ Solutions: x = 5, x = -5
---
(3) |x - 10| + 7 = 7
Subtract 7 from both sides:
|x - 10| = 0
Only one solution when absolute value equals 0:
x - 10 = 0 → x = 10
✔ Solution: x = 10
---
(4) |(1/2)x| = 3
Multiply both sides by 2 to eliminate fraction? Or just solve directly:
(1/2)x = 3 → x = 6
(1/2)x = -3 → x = -6
✔ Solutions: x = 6, x = -6
---
(5) |7 + x| = -1
Wait! Absolute value cannot equal a negative number.
✘ No solution
---
(6) |-2x| = 19
Same as |2x| = 19
So:
2x = 19 → x = 19/2
2x = -19 → x = -19/2
✔ Solutions: x = 19/2, x = -19/2
---
(7) 5|x| = 30
Divide both sides by 5:
|x| = 6
So:
x = 6 or x = -6
✔ Solutions: x = 6, x = -6
---
(8) |(1/4)x| = 3
Multiply both sides by 4:
|x| = 12
So:
x = 12 or x = -12
✔ Solutions: x = 12, x = -12
---
(9) -5|x| = -12
Divide both sides by -5:
|x| = 12/5
So:
x = 12/5 or x = -12/5
✔ Solutions: x = 12/5, x = -12/5
---
(10) |4x| = 11
So:
4x = 11 → x = 11/4
4x = -11 → x = -11/4
✔ Solutions: x = 11/4, x = -11/4
---
(11) |x| - 3 = 2
Add 3 to both sides:
|x| = 5
So:
x = 5 or x = -5
✔ Solutions: x = 5, x = -5
---
(12) |(x/2)| = 5
Multiply both sides by 2:
|x| = 10
So:
x = 10 or x = -10
✔ Solutions: x = 10, x = -10
---
(13) |(2(x+1))/3| = 5
First, multiply both sides by 3:
|2(x+1)| = 15
Now divide both sides by 2? Or keep inside:
2(x+1) = 15 → x+1 = 15/2 → x = 15/2 - 1 = 13/2
OR
2(x+1) = -15 → x+1 = -15/2 → x = -15/2 - 1 = -17/2
✔ Solutions: x = 13/2, x = -17/2
---
(14) 4|x + 4| = 56
Divide both sides by 4:
|x + 4| = 14
So:
x + 4 = 14 → x = 10
x + 4 = -14 → x = -18
✔ Solutions: x = 10, x = -18
---
(15) |7x| - 3 = 73
Add 3 to both sides:
|7x| = 76
So:
7x = 76 → x = 76/7
7x = -76 → x = -76/7
✔ Solutions: x = 76/7, x = -76/7
---
(16) |(1/2)x - 4| = 7
Set up two cases:
Case 1: (1/2)x - 4 = 7 → (1/2)x = 11 → x = 22
Case 2: (1/2)x - 4 = -7 → (1/2)x = -3 → x = -6
✔ Solutions: x = 22, x = -6
---
(17) |(x+4)/4| = 3
Multiply both sides by 4:
|x + 4| = 12
So:
x + 4 = 12 → x = 8
x + 4 = -12 → x = -16
✔ Solutions: x = 8, x = -16
---
(18) -6|6x + 2| = -78
Divide both sides by -6:
|6x + 2| = 13
Now:
6x + 2 = 13 → 6x = 11 → x = 11/6
6x + 2 = -13 → 6x = -15 → x = -15/6 = -5/2
✔ Solutions: x = 11/6, x = -5/2
---
Final Answer:
(1) x = 38/3, x = -46/3
(2) x = 5, x = -5
(3) x = 10
(4) x = 6, x = -6
(5) No solution
(6) x = 19/2, x = -19/2
(7) x = 6, x = -6
(8) x = 12, x = -12
(9) x = 12/5, x = -12/5
(10) x = 11/4, x = -11/4
(11) x = 5, x = -5
(12) x = 10, x = -10
(13) x = 13/2, x = -17/2
(14) x = 10, x = -18
(15) x = 76/7, x = -76/7
(16) x = 22, x = -6
(17) x = 8, x = -16
(18) x = 11/6, x = -5/2
Parent Tip: Review the logic above to help your child master the concept of absolute value equations worksheet.