Respuesta :

olemakpadu
-3x + 9y = -57        x = 4

-3*4 + 9y = -57

-12 + 9y = -57

9y = -57 + 12

9y = 12 - 57

9y =-45          Divide through by 9.

y = -45/9

y = -5

Hope this helped.
Alykiara
-3x+9y=-57
-3(4)+9y=-57
-12+9y=-57
+12 +12
9y=-45
Y=-5