Question

Tìm x thuộc N biết :    

a) 4x - x = 138                         b) 123 -5 * ( x + 4 ) = 38 

Answer 1

a)4x-x=138

x(4-1)=138

x .3=138

x=138:3

x=46

 

 

Answer 2

a) 4x - x = 138

=> 3x = 138

=> x = 46

b) 123 - 5 x (x + 4) = 38

=> 5 x (x + 4) = 85

=> x + 4 = 17

=> x = 13

Answer 3

a) 4x - x = 138

=> 3x = 138

=> x = 46

b) 123 - 5 x (x + 4) = 38

=> 5 x (x + 4) = 85

=> x + 4 = 17

=> x = 13

Answer 4

a, 4x-x=138

    3x   =138

      x   =138:3

      x   =46

b, 123-5.9(x+4)=38

            5.(x+4)=123-38

             5.(x+4)=85

               x+4   =85:5

               x+4   =17

                   x   =17-4

                   x   =13