計算(xの2x+1-yの2乗)/(x+y+1)

計算(xの2x+1-yの2乗)/(x+y+1)

原式=[(x+1)²-y²]/(x+y+1)[完全平方式]
=(x+1+y)(x+1-y)/(x+y+1)[平方差公式]
=x-y+1
2x前は“+”