X-(1/6X+42)=(1/6X+42)/2*3
x-1/6X-42=1/6X/2*3+42/2*3
5/6x-42=1/4x+63
5/6x=1/4x+63+42
5/6x=1/4x+105
5/6x-1/4x=105
10/12x-3/12x=105
7/12x=105
x=180