3a-b+1的绝对值 +（3a-3/2b)方=0
∴3a-b+1=0
3a-3b/2=0
∴a=-1
b=-2
(b方/a+b)/【(b/a-b)*(ab/a+b）】
=b²/(a+b)×(a+b)(a-b)/ab²
=(a-b)/a
=(-1-2)/(-1)
=3���У�������xƽ��-1fz x��(1-x)ƽ����֮-x==x/(x+1)(x-1)��(x-1)²/(-x)=-(x-1)/(x+1)=(1-x)/(x+1)