5(X+2)=2×(5X-1) 3(Y-2)+1=y-(2y-1)4(2X+3)=8(1-X)-5(X-2)
5x+10=10x-2 3y-6+1=-y+y 8x+12=8-8x-5x+10
-2x=-12 3y=5 21x=6
x=6 y=5/3 x=6/21
3(X+1)-(5+X)=18-2(X-1) -3(2y+10)-5(y-4)=7
3x+3-5-x=18-2x+2 -6y-30-5y+20=7
4x=22 -11y=17
x=5.5 y=-17/11
口算的,最好在用计算机验算一边