5 1/8x-5 3/4=3 /8-7 1/4x
5 1/8x-5 3/4=3 /8-7 1/4x 5 1/8x+7 1/4x=3/8+5 3/45 1/8x+7 2/8x=3/8+5 3/412 3/8x=3/8+5 3/412 3/8x=3/8+5 6/812 3/8x=6 1/8x=6 1/8 : 12 3/8х=56/8*8/96 х=56/96 х=7/12