7(3 - x) - 12(x - 5) = 5
=> 7.3 - 7x - 12x + 12.5 = 5
=> 21 - 7x - 12x + 60 = 5
=> ( 21 + 60) - ( 7x + 12x ) = 5
=> 81 - 19x = 5
=> 19x = 81 - 5
=> 19x = 76
=> x = 76:19
=> x = 4
vậy x = 4
\(7\left(3-x\right)-12\left(x-5\right)=5\)
\(21-7x-12x+60=5\)
\(\left(21+60\right)+\left(-7x-12x\right)=5\)
\(81-19x=5\)
\(19x=76\)
\(x=4\)
Vậy x=4