①3x+5(138-x)=540
3x+690-5x=540
2x=150
x=75
②10-4(x+3)=2(x-1)
10-4x-12=2x-2
6x=0
x=0
③2(y-3)-(4y-1)=6(1-y)
2y-6-4y+1=6-6y
4y=11
y=11/4