100x-(27-1/3x)x9= 179
100x-243+3x=179
103x=422
x=422/103
2.100x+(27-1/3x)x9=179
100x+243-3x=179
97x=-64
x=-64/97
3.6/7x+(42-1/2x)x1/7=20
6/7x+6-1/14x=20
12/14x-1/14x=20-6
11/14x=14
x=196/11
4.6/7x-(42-1/2x)x1/4=20
6/7x-21/2+1/8x=20
48/56x+7/56x=20+21/2
55/56x=61/2
x=1708/55