Question

先化简，再求值：【（x+y)²-y（2x+y）-8x】÷2x，其中x=-2

Answer 1

解：
【（x+y)²-y（2x+y）烂扰-8x】÷2x
原式薯胡=（x²+2xy+y²-2xy-y²-8x）÷2x
=(x²-8x)÷2x
=x/2 - 4
若x= -2，原式数历拦的值为（-2）÷2 - 4= - 5

Answer 2

﹙兆告x²﹢隐扰y²+2xy－2xy－y²－8x﹚÷2x＝族携明 ﹙x²－8x﹚÷2x＝x／2－4＝﹣1－4＝-5

Answer 3

[(x+y)²-y(2x+y)-8x÷2x
=[(x+y)²-y(2x+y)-x²纯数+x²-8x]÷2x
=[(x+y)²-(2xy+y²+x²)+x²-8x]÷2x
=[(x+y)²-(x+y)²庆纤+x²-8x]÷2x
=(x²做差首-8x)÷2x
=(x-8)÷2
=-5

Answer 4

【（携中x+y)²-y（2x+y）-8x】÷2x
＝（x²+2xy+y²-2xy-y²-8x）÷2x
＝（x²虚袭-8x）÷2x
=x/2-4
=-2/差隐兄2-4
=-5

Answer 5

【慧液滚（x+y)²-y（2x+y）-8x】÷2x
=（x²+y²+2xy-2xy-y²-8x）÷2x
=（x²-8x）÷2x
=（x-8）前余÷2
=（埋慧-2-8）÷2
=-10÷2
=-5