54:(x-7)=31-22

54:(x-7)=9

x-7=54:9

x-7=6

x=6+7

x=13

(29-x)*2=45+7

раскроем скобки

58-2x = 45+7

-2x+6 = 0

2x-6 = 0

2x = 6

x = 3