x+3分之2-2分之1=18分之17
x= 1/2 -2/3 +17/18
= (9-12+17) /18
= 14/18
= 7/9
2、 8分之7-25=x+4分之1x
7/8 -25 = 5x/4
7/2 - 100 = 5x
x = 7/10 -20 = 0.7-20 = - 19.3