解下列方程: (1)0.04x+0.090.05−0.3x+0.20.3=x−52; (2)(5x-2)×30%=(7x+8)×20%.

问题描述:

解下列方程:
(1)

0.04x+0.09
0.05
0.3x+0.2
0.3
x−5
2

(2)(5x-2)×30%=(7x+8)×20%.

(1)原式变形为:

4x+9
5
3x+2
3
x−5
2

6(4x+9)-10(3x+2)=15(x-5)
24x+54-30x-20=15x-75
-21x=-109,
∴x=
109
21

(2)原式变形为:
3(5x-2)=2(7x+8)
15x-6=14x+16
∴x=22