Question

Помогите пожалуйста (x+54)-12=57; 26-(x-21)=42

Answer 1

x + 54 = 57 + 12
x + 54 = 69
x = 69 - 54
x = 15


x-21 = 26 - 42
x - 21 = -16
x = 21 - 16
x = 5