Question

Решил уравнения.
x+31=40
x-75=20
96-x=72
23+x=30

Answer 1

х+31=40
x = 40 - 31
x = 9

x- 75 = 20
x = 20 + 75 
x = 95

96-x=72
x = 96 - 72
x = 24

23+x=30
x = 30 - 23
x = 7

Answer 2

x+31=40 x-75=20 96-x=72 23+x=30
x=40-31 x=20+75 x=96-72 x=30-23
x=9 x=95 x=24 x=7
9+31=40 95-75=20 96-24=72 23+7=30