化简求值[4(x^2+y)(x^2-y)-(2x^2-y)^2]÷y其中x=2分之1,y=3

化简求值[4(x^2+y)(x^2-y)-(2x^2-y)^2]÷y其中x=2分之1,y=3

[4(x^2+y)(x^2-y)-(2x^2-y)^2]÷y
=[4(x^4-y²)-(4x^4-4x²y+y²)]÷y
=[4x^4-4y²-4x^4+4x²y-y²]÷y
=[（4x^4-4x^4）+（-4y²-y²）+4x²y]÷y
=（-5y²+4x²y）÷y
=-5y+4x² 把x=1/2,y=3带入
=-5×3+4×（1/2）²
=-15+1
=-14

计划不好好