2x-3y+1+(x-8+5)=0 5x+7y-7-(8x+3y+1)=0

2x-3y+2x-9+6=0
2x-3y=9-6
2x=3+3y
x=1.5+1.5y

5(1.5+1.5y)+7y-7-(8x+3y+1)=0
7.5+7.5y+7y-7-x-4-6=0
7.5-7-4-6+7.5y+7y-x=0
-9.5+15.5y-1.5+1.5y =0
-11+17y=0
17y=11
y=11:17

x=1.5+1.5(11:17)