若有理数a.b满足l3a+1l+（2b-1)的2次方=0,求ab分之3a的2次方-2b的3次方要详细答案和过成
问题描述：
若有理数a.b满足l3a+1l+（2b-1)的2次方=0,求ab分之3a的2次方-2b的3次方要详细答案和过成
答
|3a+1|+(2b-1)^2=0
|3a+1|=0 (2b-1)^2=0
a=-1/3 b=1/2
3*(-1/3)/[(-1/3)(1/2)]-2*(1/2)=5
答
l3a+1l+（2b-1)的2次方=0
l3a+1l=0,（2b-1)的2次方=0
a=-1/3,b=1/2
(3a^2-2b^3)/ab
=[3*(-1/3)^2-2*(1/2)^3]/[(-1/3)*1/2]
=[3*1/9-2*1/8]/(-1/6)
=[1/3-1/4]/(-1/6)
=[1/3-1/4]*6
=(4/12-3/12)*6
=1/12*6
=1/2