First, expand all the terms in exponents:
(6 xx x) + (6 xx 1) = (12 xx x) - (12 xx 3)
6x + 6 = 12x - 36
Next, subtract color(red)(6x) and add color(blue)(36) to each side of the equation to isolate the x term while keeping the equation balanced:
6x + 6 - color(red)(6x) + color(blue)(36) = 12x - 36 - color(red)(6x) + color(blue)(36)
6x - color(red)(6x) + 6 + color(blue)(36) = 12x - color(red)(6x) - 36 + color(blue)(36)
0 + 42 = 6x - 0
42 = 6x
Now, divide each side of the equation by color(red)(6) to solve for x while keeping the equation balanced:
42/color(red)(6) = (6x)/color(red)(6)
7 = (color(red)(cancel(color(black)(6)))x)/cancel(color(red)(6))
7 = x
x = 7