若2x=-y,则x²-y²分之xy等于
问题描述:
若2x=-y,则x²-y²分之xy等于
答
若2x=-y,
则x²-y²分之xy
=x*(-2x)/(x²-(-2x)²)
=-2x²/(x²-4x²)
=-2x²/(-3x²)
=2/3