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