Question

Solve by the substitution method
5x+7y=10
-9x+y=50

Answer 1

(- 5, 5 )

Explanation:

5x + 7y = 10 → (1)

- 9x + y = 50 ( add 9x to both sides )

y = 9x + 50 → (2)

substitute y = 9x + 50 into (1)

5x + 7(9x + 50) = 10

5x + 63x + 350 = 10 ( subtract 350 from both sides )

68x = - 340 ( divide both sides by 68 )

x = - 5

substitute x = - 5 into (2)

y = 9(- 5) + 50 = - 45 + 50 = 5

solution is (- 5, 5 )