X(X-1)(X+3)-X的2次方(X+1)+3X+1 等于多少?
问题描述:
X(X-1)(X+3)-X的2次方(X+1)+3X+1 等于多少?
答
X(X-1)(X+3)-X的2次方(X+1)+3X+1
=x(x²+2x-3)-x³-x²+3x+1
=x³+2x²-3x-x³-x²+3x+1
=x²+1