X²+7X³+14X²+7X+1 (X+Y)³+2XY(1-X-Y)-1 X^4-11X²Y²+Y² X^3+9X^2+26X+24 X^4-12X+323 （X^5+X
问题描述：
X²+7X³+14X²+7X+1 (X+Y)³+2XY(1-X-Y)-1 X^4-11X²Y²+Y² X^3+9X^2+26X+24 X^4-12X+323 （X^5+X^4+X^3+X^2+X+1)-X^5 有所用公式更好.
答
X^4+7X³+14X²+7X+1 (X+Y)³+2XY(1-X-Y)-1 =(x+y-1)(x²+2xy+y²+x+y+1)-2xy(x+y-1)=(x+y-1)(x²+2xy+y²+x+y+1-2xy)=(x+y-1)(x²+y²+x+y+1)X^4-11X²Y²+Y^4=x^4-2x...