Question

初一数学解方程

<1> 1/5(x+2)+1/2(x-1)=2

<2>4x-1.5/0.5-0.5x-0.08/0.02=1.2-x/0.1+2

<3>x+1/0.3-2x-1/0.7=1

Answer 1

1/5(x+2)+1/2(x-1)=2 2(x+2)+5(x-1)=20 7x=21 x=3
4x-1.5/0.5-0.5x-0.08/0.02=1.2-x/0.1+2 4x-3-0.5x-4=1.2-10x+2 13.5x=10.2 x=34/45
x+1/0.3-2x-1/0.7=1 x+10/3-2x-10/7=1 x=19/21

Answer 2

<1> 7/10x+2/5-1/2=2 , x=3
<2> 13.5x=10.2, x约=0.76
<3> x=-1+10/3-10/7=19/21
孩子你为虾米不自己算，那不是快多啦。。。

Answer 3

1、[1/5(x+2)+1/2(x-1)]*5=2*5
(x+2)+5/2(x-1)=10
[(x+2)+5/2(x-1)]*2=10*2
2(x+2)+5(x-1)=20
2x+4+5x-5=20
7x-1=20
7x=21
x=3