Quadratic equations for math practice.
Math practice worksheet featuring six quadratic equations to solve.
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Step-by-step solution for: Solving Quadratic Equations by Factoring worksheet
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Show Answer Key & Explanations
Step-by-step solution for: Solving Quadratic Equations by Factoring worksheet
You've uploaded a math worksheet titled “Math Practice” with six quadratic equations to solve. All are in standard form:
> ax² + bx + c = 0
We’ll solve each using factoring, since all appear factorable (as is common in practice worksheets). Let’s go one by one.
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2x² – 2x – 24 = 0
✔ Step 1: Factor out the GCF (Greatest Common Factor)
All terms divisible by 2 →
→ 2(x² – x – 12) = 0
✔ Step 2: Factor the trinomial
We need two numbers that multiply to –12 and add to –1:
→ –4 and +3
So:
→ 2(x – 4)(x + 3) = 0
✔ Step 3: Set each factor = 0
→ x – 4 = 0 → x = 4
→ x + 3 = 0 → x = –3
✔ Solutions: x = 4, x = –3
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x² + 10x + 16 = 0
✔ Find two numbers that multiply to 16 and add to 10:
→ 8 and 2
→ (x + 8)(x + 2) = 0
✔ Solutions:
→ x + 8 = 0 → x = –8
→ x + 2 = 0 → x = –2
✔ Solutions: x = –8, x = –2
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4x² + 15x + 9 = 0
✔ Need two numbers that multiply to 4×9 = 36 and add to 15 → 12 and 3
Rewrite middle term:
→ 4x² + 12x + 3x + 9 = 0
Group:
→ (4x² + 12x) + (3x + 9) = 0
→ 4x(x + 3) + 3(x + 3) = 0
→ (4x + 3)(x + 3) = 0
✔ Solutions:
→ 4x + 3 = 0 → x = –3/4
→ x + 3 = 0 → x = –3
✔ Solutions: x = –3/4, x = –3
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x² – 13x + 42 = 0
✔ Two numbers that multiply to 42 and add to –13:
→ –6 and –7
→ (x – 6)(x – 7) = 0
✔ Solutions:
→ x – 6 = 0 → x = 6
→ x – 7 = 0 → x = 7
✔ Solutions: x = 6, x = 7
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6x² – x – 40 = 0
✔ Multiply a×c = 6×(–40) = –240
Need two numbers that multiply to –240 and add to –1 → –16 and +15
Rewrite:
→ 6x² – 16x + 15x – 40 = 0
Group:
→ (6x² – 16x) + (15x – 40) = 0
→ 2x(3x – 8) + 5(3x – 8) = 0
→ (2x + 5)(3x – 8) = 0
✔ Solutions:
→ 2x + 5 = 0 → x = –5/2
→ 3x – 8 = 0 → x = 8/3
✔ Solutions: x = –5/2, x = 8/3
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2x² + 13x + 15 = 0
✔ Multiply a×c = 2×15 = 30
Need two numbers that multiply to 30 and add to 13 → 10 and 3
Rewrite:
→ 2x² + 10x + 3x + 15 = 0
Group:
→ (2x² + 10x) + (3x + 15) = 0
→ 2x(x + 5) + 3(x + 5) = 0
→ (2x + 3)(x + 5) = 0
✔ Solutions:
→ 2x + 3 = 0 → x = –3/2
→ x + 5 = 0 → x = –5
✔ Solutions: x = –3/2, x = –5
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## ✔ Final Answers:
| Equation | Solutions |
|----------|---------|
| 2x² – 2x – 24 = 0 | x = 4, x = –3 |
| x² + 10x + 16 = 0 | x = –8, x = –2 |
| 4x² + 15x + 9 = 0 | x = –3/4, x = –3 |
| x² – 13x + 42 = 0 | x = 6, x = 7 |
| 6x² – x – 40 = 0 | x = –5/2, x = 8/3 |
| 2x² + 13x + 15 = 0 | x = –3/2, x = –5 |
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Let me know if you’d like to see these solved using the quadratic formula or graphed!
> ax² + bx + c = 0
We’ll solve each using factoring, since all appear factorable (as is common in practice worksheets). Let’s go one by one.
---
🔹 Equation 1:
2x² – 2x – 24 = 0
✔ Step 1: Factor out the GCF (Greatest Common Factor)
All terms divisible by 2 →
→ 2(x² – x – 12) = 0
✔ Step 2: Factor the trinomial
We need two numbers that multiply to –12 and add to –1:
→ –4 and +3
So:
→ 2(x – 4)(x + 3) = 0
✔ Step 3: Set each factor = 0
→ x – 4 = 0 → x = 4
→ x + 3 = 0 → x = –3
✔ Solutions: x = 4, x = –3
---
🔹 Equation 2:
x² + 10x + 16 = 0
✔ Find two numbers that multiply to 16 and add to 10:
→ 8 and 2
→ (x + 8)(x + 2) = 0
✔ Solutions:
→ x + 8 = 0 → x = –8
→ x + 2 = 0 → x = –2
✔ Solutions: x = –8, x = –2
---
🔹 Equation 3:
4x² + 15x + 9 = 0
✔ Need two numbers that multiply to 4×9 = 36 and add to 15 → 12 and 3
Rewrite middle term:
→ 4x² + 12x + 3x + 9 = 0
Group:
→ (4x² + 12x) + (3x + 9) = 0
→ 4x(x + 3) + 3(x + 3) = 0
→ (4x + 3)(x + 3) = 0
✔ Solutions:
→ 4x + 3 = 0 → x = –3/4
→ x + 3 = 0 → x = –3
✔ Solutions: x = –3/4, x = –3
---
🔹 Equation 4:
x² – 13x + 42 = 0
✔ Two numbers that multiply to 42 and add to –13:
→ –6 and –7
→ (x – 6)(x – 7) = 0
✔ Solutions:
→ x – 6 = 0 → x = 6
→ x – 7 = 0 → x = 7
✔ Solutions: x = 6, x = 7
---
🔹 Equation 5:
6x² – x – 40 = 0
✔ Multiply a×c = 6×(–40) = –240
Need two numbers that multiply to –240 and add to –1 → –16 and +15
Rewrite:
→ 6x² – 16x + 15x – 40 = 0
Group:
→ (6x² – 16x) + (15x – 40) = 0
→ 2x(3x – 8) + 5(3x – 8) = 0
→ (2x + 5)(3x – 8) = 0
✔ Solutions:
→ 2x + 5 = 0 → x = –5/2
→ 3x – 8 = 0 → x = 8/3
✔ Solutions: x = –5/2, x = 8/3
---
🔹 Equation 6:
2x² + 13x + 15 = 0
✔ Multiply a×c = 2×15 = 30
Need two numbers that multiply to 30 and add to 13 → 10 and 3
Rewrite:
→ 2x² + 10x + 3x + 15 = 0
Group:
→ (2x² + 10x) + (3x + 15) = 0
→ 2x(x + 5) + 3(x + 5) = 0
→ (2x + 3)(x + 5) = 0
✔ Solutions:
→ 2x + 3 = 0 → x = –3/2
→ x + 5 = 0 → x = –5
✔ Solutions: x = –3/2, x = –5
---
## ✔ Final Answers:
| Equation | Solutions |
|----------|---------|
| 2x² – 2x – 24 = 0 | x = 4, x = –3 |
| x² + 10x + 16 = 0 | x = –8, x = –2 |
| 4x² + 15x + 9 = 0 | x = –3/4, x = –3 |
| x² – 13x + 42 = 0 | x = 6, x = 7 |
| 6x² – x – 40 = 0 | x = –5/2, x = 8/3 |
| 2x² + 13x + 15 = 0 | x = –3/2, x = –5 |
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Let me know if you’d like to see these solved using the quadratic formula or graphed!
Parent Tip: Review the logic above to help your child master the concept of solve by factoring worksheet.