Question

3(x-7)-5(4-x)=15 0.2分之0.1x+0.3+2.5=0.4x-1

Answer 1

解方程?

3(x-7)-5(4-x)=15

3x-21-20+5x=15

3x+5x=15+20+21

8x=56

x=7

0.2分之0.1x+0.3+2.5=0.5分之0.4x-1

(0.1x+0.3)/0.2+2.5=(0.4x-1)/0.5

(x+3)/2+2.5=(4x+10)/5

等式左右同乘10

5x+15+25=8x+20

8x-5x=15+25-20

3x=20

x=20/3