“Stephen attempted to use the elimination method to solve the system of equations below but he made a mistake. What is it?
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Answer:
second option
Step-by-step explanation:
x + y = 18 → (1)
4x - 3y = - 12 → (2)
Multiplying (1) by - 4 and adding to (2) will eliminate the x- term
- 4x - 4y = - 72 → (3)
add (2) and (3) term by term to eliminate x
0 - 7y = - 84
- 7y = - 84 ( divide both sides by - 7 )
y = 12
Substitute y = 12 into (1) and solve for x
x + 12 = 18 ( subtract 12 from both sides )
x = 6
solution is x = 6, y = 12