8[7 - (6x - 6)] + 6x = 0.
8[7 - (6x - 6)] + 6x = 0 simplify inside the brackets first
8 [ 7 - 6x + 6 ] + 6x = 0
8 [ 13 - 6x ] + 6x = 0
104 - 48x + 6x = 0
104 - 42x = 0 add 42x to both sides
104 = 42x divide both sides by 42
104 / 42 = x = 52 / 21