(2a-b+1)的绝对值+(3a+(3/2)b)的平方等于0
2a-b+1=0
3a+(3/2)b=0
a=-1/4
b=1/2
[(3ab+a的平方)/a的平方-b]除[(a+3b)/(a-b)]
=a(a-b)/a的平方-b
=-3/7