1.2x+1=2-x
2x+x=2-1
3x=1
x=1/3
2.2（x+8)=3(x-1)
2x+16=3x-3
2x-3x=-3-16
x=19
3.x-3/2-4x+1/5=1
5(x-3)-2(4x+1)=10
5x-15-8x-2=10
-3x=27
x=-9
4.3y-1/4-1=5y-7/6
两边同乘以12 得
3（3y-1）-12=2(5y-7)
9y-3-12=10y-14
9y-10y=-14+3+12
y=-1