Respuesta :

Answer:

Step-by-step explanation:

1. 3/7 x = 12

  3x = 84

    x = 28

2. 3x+ 6 = 39

   3x = 33

    x = 11

3. 1/3 x - 3/4 x = 15

    9x  - 4x  = 180

       x =  36

4.   1/4 x = x -21

      3/4 x = 21

      3x = 84

        x=28

5.    86-36 = 50

      50/2

       25