Respuesta :

10x - 3(x-6) = x30
10x - 3x + 18 = 30x
7x + 18 = 30x
18 = 30x - 7x
18 = 23x
18/23 = x
0.78 = x

En caso de ser:

10x - 3(x-6) = x+30
10x - 3x + 18 = x+30
7x + 18 = x+30
7x - x + 18 = 30
6x + 18 = 30
6x = 30-18
6x = 12
X= 12/6
X=2