Question

70 - 5 . [ 2x - 3 ] = 45

Answer 1

70-5.(2x-3)=45

=>5.(2x-3)=70-45

=>5.(2x-3)=25

=>2x-3=25:5

=>2x-3=5

=>2x=5+3

=>2x=8

=>x=8:2

=>x=4

Vậy x=4

Answer 2

5 | 2x - 3 | = 70 - 45 = 25

  | 2x - 3 | = 25 : 5 = 5

TH1: 2x - 3 = 5

          2x    = 5 + 3 = 8

            x   = 8 : 2 = 4

TH2:  2x - 3  = -5

              2x = -5 + 3 = -2

               x  = -2 : 2 = -1

=> x có 2 nghiệm { -1; 4 }