Question

x+3x=20
x+(x-20)+3x=180
3(x+20)-4x=10
Помогите пожалуйста

Answer 1

4x = 20
x = 20/4
x = 5

x + x - 20 + 3x = 180
5x = 180 + 20
5x = 200
x = 200/5
x = 40

3x + 60 - 4x = 10
- x = - 50
x = 50