Worked example
Solve for x: 2x + y = 10, and x + y = 7.
Answer & why
Answer: 3
Subtract the second equation from the first: 1x = 3, so x = 3.
Grade 9 · Math
Solve a linear system by elimination
Eliminate one variable to solve two simultaneous linear equations.
8 authored questions + worked example
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All questions
All 8 authored questions for this skill.
Question 1
Solve for x: 4x + y = 22, and x + y = 10.
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A hint
Eliminate y by subtracting the two equations.
Answer & why
Answer: 4
Subtract the second equation from the first: 3x = 12, so x = 4.
Question 2
Solve for x: 5x + y = 17, and x + y = 9.
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A hint
Eliminate y by subtracting the two equations.
Answer & why
Answer: 2
Subtract the second equation from the first: 4x = 8, so x = 2.
Question 3
Solve for x: 2x + y = 10, and x + y = 7.
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A hint
Eliminate y by subtracting the two equations.
Answer & why
Answer: 3
Subtract the second equation from the first: 1x = 3, so x = 3.
Question 4
Solve for x: 3x + y = 14, and x + y = 6.
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A hint
Eliminate y by subtracting the two equations.
Answer & why
Answer: 4
Subtract the second equation from the first: 2x = 8, so x = 4.
Question 5
Solve for x: 4x + y = 13, and x + y = 7.
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A hint
Eliminate y by subtracting the two equations.
Answer & why
Answer: 2
Subtract the second equation from the first: 3x = 6, so x = 2.
Question 6
Solve for x: 5x + y = 16, and x + y = 4.
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A hint
Eliminate y by subtracting the two equations.
Answer & why
Answer: 3
Subtract the second equation from the first: 4x = 12, so x = 3.
Question 7
Solve for x: 2x + y = 15, and x + y = 9.
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A hint
Eliminate y by subtracting the two equations.
Answer & why
Answer: 6
Subtract the second equation from the first: 1x = 6, so x = 6.
Question 8
Solve for x: 3x + y = 19, and x + y = 9.
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A hint
Eliminate y by subtracting the two equations.
Answer & why
Answer: 5
Subtract the second equation from the first: 2x = 10, so x = 5.