Ответ:

Пошаговое объяснение:

1)5/7=20/(x+2)

5*(x+2) = 20*7

5x + 10 = 140

5x = 140-10

5x = 130

x = 130 : 5

x = 26

2)(5x-1)/12=27/36

36*(5x-1) = 27*12

180x - 36 = 324

180x = 324+36

180x = 360

x = 360:180

x = 2