(9a^2b^3-12a^4b^5)/3a^2b-b^2(2-3a^2b^2),其中a=-1/2,b=2

问题描述:

(9a^2b^3-12a^4b^5)/3a^2b-b^2(2-3a^2b^2),其中a=-1/2,b=2
注意:(9a^2b^3-12a^4b^5)÷3a^2b-b^2(2-3a^2b^2)

(9a^2b^3-12a^4b^5)÷3a^2b-b^2(2-3a^2b^2)
=3b²-4a²b^4-2b²+3a²b^4
=b²-a²b^4
当a=-1/2,b=2时
原式=4-4=0