(b-2)/(a+1)=4
b-2=4(a+1)
4(a加1)分之3(b减2)加b减2分之3(a加1)
=3×4(a+1)/4(a+1) + 3(a+1)/4(a+1)
=3+3/4
=3又4分之3确定？确定(b-2)/(a+1)=4所以,b-2=4(a+1).然后把b-2 用4(a+1)代进去,约分就可以了,呵呵