If you would like to solve the equation 1/3 * (12 + X) = -8 * (6 + X) for X, you can calculate this using the following steps:
1/3 * (12 + X) = -8 * (6 + X)
1/3 * 12 + 1/3 * X = -8 * 6 - 8 * X
4 + 1/3 * X = - 48 - 8 * X
1/3 * X + 8 * X = - 48 - 4
8 1/3 * X = - 52
25/3 * X = - 52 /*3/25
X = - 52 * 3 / 25
X = - 156/25
X = - 6 6/25
The correct result would be - 6 6/25.