1.x+7分之3=4分之3
x=3/4-3/7
x=21/28-12/28
x=9/28
2.x-12分之5=8分之3
x=3/8+5/12
x=9/24+10/24
x=19/24
3.x-6分之5=1
x-5/6=1
x=1+5/6
x=11/6