第1个回答 2015-03-26
(1)4x-3(20-x)+4=0
4x-60+3x+4=0
4x+3x=60-4
7x=56
x=8.
(2) 1-y/2=y+1/3
6-3y=6y+2
-3y-6y=3-6
-9y=-3
y=1/3.
(3) (3x-1)/2=(4x+2)/5-1
5(3x-1)=2(4x+2)-10
15x-5=8x+4-10
15x-8x=4-10+5
7x=-1
x=-1/7.
(4) x-(1-x)/3=(x+2)/6-1
6x-2(1-x)=(x+2)-6
6x-2+2x=x+2-6
6x+2x-x=2-6+2
7x=-2
x=-2/7.