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Use substitution to solve the system
4x-5y=-40
-3x+y=19

1 Answer

2 votes

Answer:

x = - 5 , y = 4

Explanation:

given the system of equations

4x - 5y = - 40 → (1)

- 3x + y = 19 ( add 3x to both sides )

y = 3x + 19 → (2)

substitute y = 3x + 19 into (1)

4x - 5(3x + 19) = - 40 ( simplify left side )

4x - 15x - 95 = - 40

- 11x - 95 = - 40 ( add 95 to both sides )

- 11x = 55 ( divide both sides by - 11 )

x = - 5

substitute x = - 5 into (2)

y = 3(- 5) + 19 = - 15 + 19 = 4

solution is x = - 5 , y = 4

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