1/3(12+x) = -8 (6-x)
Distribute the 1/3 and the -8 through their parentheses
4 + 1/3x = -48 + 8x
subtract 4 from each side
1/3x = -52 + 8x
subtract 8x from each side
1/3x - 8x = -52
combine like terms
1/3x - 24/3x = -52
-23/3x = -52
divide each side by -23/3 (multiply the reciprocal of the divisor)
x = -52 × -3/23
x = 156/23
x = 6 18/23 or 6.78