Question

（3X的立方减2X减1）因式分解

Answer 1

3X^3-2X-1

=(X^3-1)+(2X^2-2X)

=(X-1)(X^2+X+1)+2X(X^2-1)

=(X-1)(X^2+X+1)+2X(X-1)(X+1)

=(X-1)(X^2+X+1+2X^2+2X)

=(X-1)(3X^2+3x+1)