Inlocuim pe x cu - 2
3 × ( - 2) ( m - 2) - 2 m × ( - 2) + 9 = 5 m + 56
- 6 m + 12 + 4 m - 5 m = 56 - 9
- 7 m = 47 - 12
- 7 m = 35
m = 35 : ( - 7 )
m = - 5
sau
3 mx - 6 x - 2 mx+ 9 = 5 m + 56
m x - 5 m = 56 - 9 + 6 x
- 2 m - 5 m = 47 + 6 × ( - 2)
- 7 m = 47 - 12
m = 35 : ( - 7)
m = - 5
