璀璨_唯艺
[(x+y)x²/(x²-y²)]+y²/(y-x)
=[(x+y)x²/(x+y)(x-y)]+y²/(y-x)
=x²/(x-y)+y²/(y-x)
=x²/(x-y)-y²/(x-y)
=(x²-y²)/(x-y)
=[(x+y)(x-y)]/(x-y)
=x+y