x²+x=3所以x³+x²=3x所以原式=(3-3x)/(x-1)=-3(x-1)/(x-1)=-3
∵x²+x-3=0 x²+x=3∴﹙x²+x﹚x=3x x³+x²=3x∴3-x²-x³/(x-1)=(3-3x)/(x-1)=-3(x-1)/(x-1)=-3
