2x-14/28 +x/35 -(x/28 +2x-14 /35 )=12/ 60
(2x-14)/28+x/35-x/28-(2x-14)/35=12/60
(2x-14-x)/28-(2x-14+35)/35=1/5
5(x-14)-4(2x+21)=28
5x-70-8x-84=28
-3x=28+154
-3x=182
x=-61