MT【102】一个常见的因式分解公式 解答: $x^3+y^3+1-3xy=(x+y+1)(x^2+y^2+1+xy-x-y)=$ $(x+y+1)(x^2+y^2+1+xy-x-y)=$ $frac{1}{2}(x+y+1)[(x-y)^2+(x-1)^2+(y-1)^2] herefore x=y=1$