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