(X-30) [1500 + 400 (40-x)] = 17500 solve the equation A complete calculation process is required

(X-30) [1500 + 400 (40-x)] = 17500 solve the equation A complete calculation process is required

(X-30)[1500+400(40-X)]=17500
(x-30)(17500-400x)=17500
(x-30)(175-4x)=175
175x-4x^2-5250+120x=175
4x^2-295x+5425=0
(4x-155)(x-35)=0
x1=155/4
x2=35

How to solve the equation (x + 25) / (x + 100) = 40%

(x+25)/(x+100)=40%
(x+25)=(x+100)×40%
x＋25=0.4x＋40
0.6x=15
x=25

How to solve the equation 4x + (32-x) / 2 = 100,

4x+（32-x）/2=100
To denominator: 8x + 32-x = 200
Transfer: 8x-x = 200-32
Merge similar items: 7x = 168
The coefficient is 1: x = 24