问题标题：
初中数学约分.a²+3ab/a²b+3ab²xy+xy²/x²y³+x²y(4次）3ab+3b²/a²b+2ab+b³x²-2x-3/x³+2x²-15x约分求值~~3a²-ab/9a²-6ab+b³其中a=3/4,b=
问题描述：
初中数学约分.
a²+3ab/a²b+3ab²xy+xy²/x²y³+x²y(4次）
3ab+3b²/a²b+2ab+b³x²-2x-3/x³+2x²-15x
约分求值~~
3a²-ab/9a²-6ab+b³其中a=3/4,b=-2/3
罗德荣回答：
a²+3ab/a²b+3ab²
=a(a+3b)/[ab(a+3b)]
=1/b
xy+xy²/x²y³+x²y(4次）
=xy(1+y)/[x²y³(1+y)]
=1/(xy²)
3ab+3b²/a²b+2ab+b³
=3b(a+b)/[b(a²+2a+b²)]
=(3a+3b)/(a²+2a+b²)
x²-2x-3/x³+2x²-15x
=(x-3)(x+1)/[x(x²+2x-15)]
=(x-3)(x+1)/[x(x-3)(x+5)]
=(x+1)/(x²+5x)
3a²-ab/9a²-6ab+b³
=a(3a-b)/(3a-b)²
=a/(3a-b)
=(3/4)/[(9/4)+(2/3)]
=(3/4)/(35/12)
=35/16
查看更多
