-12 . ( x - 5 ) + 7. ( 3 - x ) = 5
- 12x - ( - 60 ) + 21 - 7x = 5
- 12x + 60 + 21 - 7x = 5
- 12 x + 81 - 7x = 5
- 12x - 7x = 5 - 81
- 12x - 7x = - 76
( - 12 - 7 ).x = - 76
- 19 . x = -76
x = - 76 : ( - 19 )
x = 4
Vậy x = 4
-12.(x - 5) + 7.(3 - x) = 5
(-12).x - (-12).5 + 7.3 - 7x = 5
(-12).x + 60 + 21 - 7x = 5
(-12).x - 7x = 5 - 60 - 21
(-19).x = -76
x = (-76) : (-19)
x = 4