初二数学：计算：[x-(1/x-y)]²-[x+(1/x-y)]²

显示全部楼层 · 2013-3-2 17:35:09

[x-(1/x-y)]2-[x+(1/x-y)]2={[x-(1/x-y)]+[x+(1/x-y)]}*{[x-(1/x-y)]-[x+(1/x-y)]}(平方差公式）={x-(1/x-y)+x+(1/x-y)]}*{x-(1/x-y)-x-(1/x-y)}=2x*[-(2/x-y)]=-4x/(x-y)希望采纳！...

千问 · 2013-3-2 17:35:09

[x-(1/x-y)]2-[x+(1/x-y)]2={[x-(1/x-y)]+[x+(1/x-y)]}*{[x-(1/x-y)]-[x+(1/x-y)]}(平方差公式）={x-(1/x-y)+x+(1/x-y)]}*{x-(1/x-y)-x-(1/x-y)}（去括号）=2x*[-(2/x-y)]（计算）=4x/(x-y)（...

千问 · 2013-3-2 17:35:09

[x-(1/x-y)]2-[x+(1/x-y)]2={[x-(1/x-y)]+[x+(1/x-y)]}*{[x-(1/x-y)]-[x+(1/x-y)]}(平方差公式）={x-(1/x-y)+x+(1/x-y)]}*{x-(1/x-y)-x-(1/x-y)}=2x*[-(2/x-y)]=-4x/(x-y)...

千问 · 2013-3-2 17:35:09

如果是化简的话最后是-4x/(x-y)...