问题
解答题
先化简,再求值:[(x+y)2-y(2x+y)-8x]÷2x,其中x=-2.
答案
[(x+y)2-y(2x+y)-8x]÷2x,
=[x2+2xy+y2-2xy-y2-8x]÷2x,
=(x2-8x)÷2x,
=
-4,x 2
当x=-2时,原式=
-4=-1-4=-5.-2 2
先化简,再求值:[(x+y)2-y(2x+y)-8x]÷2x,其中x=-2.
[(x+y)2-y(2x+y)-8x]÷2x,
=[x2+2xy+y2-2xy-y2-8x]÷2x,
=(x2-8x)÷2x,
=
-4,x 2
当x=-2时,原式=
-4=-1-4=-5.-2 2