Question

Solve using the substitution method.
9x+4y=−25
x=40− 9y

Answer 1

`9x + 4y = - 25`

9×+4y=-25

Answer 2

Answer (rounded to the nearest tenth): y=6.2
Explanation: you have to replace the x in the initial equation with the second equation (40-9y). Then you can solve for y
9(40-9y) + 4y = -25
460-81y+4y=-25
450-77y=-25
-77y=-475
y (rounded to the nearest tenth)=6.2