17+с=24
32-х=24
7×х=56

1. 17 + с = 24

17 + с - 17 = 24 - 17

с = 7

2. 32 - х = 24

32 - х - 32 = 24 - 32

-х = -8

-х * (-1) = -8 * (-1)

х = 8

3. 7 × х = 56

(7 × х) / 7 = 56 / 7

х = 8