X＋7/12等5/6
x=10/12-7/12
x=3/12
x=1/4
7X-1.25等3/4
7x=5/4+3/4
7x=2
x=2/7
x-(2/5＋1/4)等7/10
x=2/5+1/4+7/10
x=8/20+5/20+14/20
x=27/20