Question

先化简,再求值:[(2x-y)²+(2x+y)(2x-y)]÷4x,其中x=二分之一,y=2 ……

筱女子谢谢大家了……………… 偶会加分的…………加分的

Answer 1

[(2x-y)²+(2x+y)(2x-y)]÷4x
=(4x²-4xy+y²＋4x²-y²)×1/4x
=(8x²-4xy)/4x
=2x-y
∵x=1/2 ∴y=2
2x-y=2×1/2-2=-1

Answer 2

[(2x-y)²+(2x+y)(2x-y)]÷4x=[（4x²-4xy+y²）+（4x²-y²）]÷4x=（8x²-4xy）÷4x=2x-y
=2×1/2-2=-1