Question

X的4次方加X3次方减9X的平方加7X减2的因式分解

Answer 1

原式=（X^4-2^3)+(3X^3-6X^2)-(3X^2-6X)+(X-2)

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

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