Let’s solve each system of equations using elimination. We’ll go one by one, step by step.
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Problem 1:
Equations:
- -2x - 3y = -7
- -2x - 5y = -5
Step 1: Subtract the second equation from the first to eliminate x.
(-2x - 3y) - (-2x - 5y) = -7 - (-5)
→ -2x - 3y + 2x + 5y = -7 + 5
→ 2y = -2 → y = -1
Step 2: Plug y = -1 into one of the original equations. Let’s use the first:
-2x - 3(-1) = -7 → -2x + 3 = -7 → -2x = -10 → x = 5
✔ Solution: (5, -1)
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Problem 2:
Equations:
- -5x + 3y = 10
- -5x - 2y = 35
Step 1: Subtract the second equation from the first.
(-5x + 3y) - (-5x - 2y) = 10 - 35
→ -5x + 3y + 5x + 2y = -25
→ 5y = -25 → y = -5
Step 2: Plug y = -5 into first equation:
-5x + 3(-5) = 10 → -5x -15 = 10 → -5x = 25 → x = -5
✔ Solution: (-5, -5)
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Problem 3:
Equations:
- x + 2y = -1
- x + y = 2
Step 1: Subtract the second equation from the first.
(x + 2y) - (x + y) = -1 - 2
→ x + 2y - x - y = -3 → y = -3
Step 2: Plug y = -3 into second equation:
x + (-3) = 2 → x = 5
✔ Solution: (5, -3)
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Problem 4:
Equations:
- -3x - 3y = 12
- 5x - 3y = 20
Step 1: Subtract the first equation from the second to eliminate y.
(5x - 3y) - (-3x - 3y) = 20 - 12
→ 5x - 3y + 3x + 3y = 8 → 8x = 8 → x = 1
Step 2: Plug x = 1 into first equation:
-3(1) - 3y = 12 → -3 - 3y = 12 → -3y = 15 → y = -5
✔ Solution: (1, -5)
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Problem 5:
Equations:
- -5x - 4y = 8
- 4x - 4y = -28
Step 1: Subtract the second equation from the first.
(-5x - 4y) - (4x - 4y) = 8 - (-28)
→ -5x - 4y - 4x + 4y = 36 → -9x = 36 → x = -4
Step 2: Plug x = -4 into second equation:
4(-4) - 4y = -28 → -16 - 4y = -28 → -4y = -12 → y = 3
✔ Solution: (-4, 3)
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Problem 6:
Equations:
- 4x + 2y = -12
- -5x + 2y = 6
Step 1: Subtract the second equation from the first.
(4x + 2y) - (-5x + 2y) = -12 - 6
→ 4x + 2y + 5x - 2y = -18 → 9x = -18 → x = -2
Step 2: Plug x = -2 into first equation:
4(-2) + 2y = -12 → -8 + 2y = -12 → 2y = -4 → y = -2
✔ Solution: (-2, -2)
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Problem 7:
Equations:
- 3x + 4y = -12
- -3x - 2y = 12
Step 1: Add the two equations together to eliminate x.
(3x + 4y) + (-3x - 2y) = -12 + 12
→ 0x + 2y = 0 → 2y = 0 → y = 0
Step 2: Plug y = 0 into first equation:
3x + 4(0) = -12 → 3x = -12 → x = -4
✔ Solution: (-4, 0)
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Problem 8:
Equations:
- -5x + 5y = 0
- 5x + 4y = 0
Step 1: Add the two equations to eliminate x.
(-5x + 5y) + (5x + 4y) = 0 + 0
→ 0x + 9y = 0 → 9y = 0 → y = 0
Step 2: Plug y = 0 into first equation:
-5x + 5(0) = 0 → -5x = 0 → x = 0
✔ Solution: (0, 0)
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Final Answer:
1. (5, -1)
2. (-5, -5)
3. (5, -3)
4. (1, -5)
5. (-4, 3)
6. (-2, -2)
7. (-4, 0)
8. (0, 0)
Parent Tip: Review the logic above to help your child master the concept of systems of linear and quadratic equations worksheet.