Respuesta :

SlowZasob
13x + 7 = 10x - 11     / + 11 (both sides)
13x + 18 = 10x    / - 13x (both sides)
-3x = 18     / : (-3) (both sides)
x = -6

Generally try to isolate x from the rest of the numbers and calculations.
AL2006
13x + 7  =  10x - 11

Subtract  10x from each side:    3x + 7  =  -11

Subtract  7  from each side:     3x  =  -18

Divide each side by  3 :       x  =  -6