Respuesta :

9s + 3=57
9s=57-3
9s=54
s=54/9
s=6

2) 
4d +6= 42
4d=42-6
4d=36
d=36/4
d=9

3)   
-3y +12 = -48
-3y=-48-12
-3y= -60
3y=60
y=60/3
y=20

9s + 3 = 57          Subtract 3 from each side
9s = 54                Divide each side by 9
s = 6

4d + 6 = 42          Subtract 6 from each side
4d = 36                 Divide each side by 4
d = 9

-3y + 12 = -48      Subtract 12 from each side
-3y = -60               Divide each side by -3
y = 20