[(x-y)的平方+(x+y)(x-y)]除以2x

问题描述:

[(x-y)的平方+(x+y)(x-y)]除以2x


[(x-y)²+(x+y)(x-y)]÷2x
=[x²-2xy+y²+x²-y²]÷2x
=(2x²-2xy)÷2x
=x-y