Respuesta :

7x+12+63=180
8x+12=180
Subtract 12 from both sides
8x= 168
=c=21

10x-40=50
Add 40 to both sides
10x=90
X=9

4x+72+2x-12=180
6x +60 =180
Subtract 60 from both sides
6x=120
X=20