Respuesta :

2x / 7 = 12 / 14

Start by cross multiplying

28x = 84

Divide both sides by 28

x = 3

b) 3 / x - 1 = 5 / 7

Start by cross multiplying 

21 = 5x - 5

Flip the equation

5x - 5 = 21
    +5    +5

5x = 26

x = 26/5