先化简再求值a²-6ab+9b²分之a²-3ab a=1.5b=-3分之二

先化简再求值a²-6ab+9b²分之a²-3ab a=1.5b=-3分之二
先化简再求值a²-6ab+9b²分之a²-3ab a=1.5b=-3分之二

先化简再求值a²-6ab+9b²分之a²-3ab a=1.5b=-3分之二
解
(a²-3ab)/(a²-6ab+9b²)
=a(a-3b)/(a-3b)²
=a/(a-3b)
=1.5/[1.5-3×(-2/3)]
=1.5/(1.5+2)
=1.5/(3.5)
=3/7