1/10-x=1/18 X=9/90-5/90 X=4/90 X=2/45 2x-1/2-1/4=1/8 2X-4/8-2/8=1/8 2X-6/8=1/8 2X=7/8 X=7/16 x-2/7=3又1/2 X-2/7=7/2 X=7/2+2/7 X=49/14+4/14 X=53/14 X=3又11/14 x-1/3=1/4 X=1/4+1/3 X=7/12