(x-y)^2*(x+y)=(x-y)*(x^2-y^2)=x^3-x^2*y-x*y^2-y^3（-x-y）*（x+y）=-(x+y)^2=-x^2-2xy-y^2(-x-y)(x-y)=-(x+y)(x-y)=y^2-x^2杨辉三角简单的说,就是两个未知数和的幂次方运算后的系数问题,比如（x+y）的平方=x的平...