化简(x^2-y^2)/(x+y)
问题描述:
化简(x^2-y^2)/(x+y)
解法一:(x^2-y^2)/(x+y)=(x+y)(x-y)/(x+y)=x-y
解法二:(x^2-y^2)/(x+y)=(x^2-y^2)(x-y)/(x+y)(x-y)=(x^2-y^2)(x-y)/(x^2-y^2)=x-y
你认为小红同学的两种解法对吗?若解法错误,请说明原因
答
解法1 没问题
解法2 只有在x-y不等于0时可行