Respuesta :

x + 7 = 2(3x - 4)         Remove the brackets

x + 7 = 2*3x - 4*2

x + 7 = 6x -  8            Subtract 7 from both sides.

x + 7 - 7 = 6x - 8 - 7  

x = 6x - 15                 Subtract 6x from both sides

x - 6x = - 15

-5x = - 15                   Divide by -5

-5x/-5 = -15/-5

x = 3