Question

化简求值【(xy+2)(xy-2)-2x²y²+4)÷(xy)】，其中x=4，y=-1/4

快，在线等！！

Answer 1

[(xy+2)(xy-2)-2x²y²+4]÷(xy),
=﹙x²y²-4-2x²y²+4)÷(xy)
=(-x²y²)÷(xy)
=-xy
=-4*-1/4
=1
不懂的欢迎追问，如有帮助请采纳，谢谢!

追问

只要确定对就采纳！！

追答

肯定对,你放心好了!

Answer 2

【(xy+2)(xy-2)-2x²y²+4)÷(xy)】
=【(x²y²-4)-2x²y²+4)÷(xy)】
=【x²y²-4-2x²y²+4)÷(xy)】
=【(-x²y²)÷(xy)】
=-xy
=-4*(-1/4)
=1

Answer 3

[(xy+2)(xy-2)-2x²y²+4]÷xy
=[(xy)²-4-2x²y²+4]÷xy
=[x²y²-4-2x²y²+4]÷xy
=-x²y²÷xy
=-xy
当x=4，y=-1/4

-xy
=-（4乘以-1/4）
=1

Answer 4

[(xy+2)(xy-2)-2x²y²+4]÷xy
=[(xy)²-4-2(xy)²+4]÷xy
=-(xy)²÷xy
=-xy
当x=4；y=-1/4时代入得：
原式=-4×-1/4=1

追问

麻烦详细一点啊……