Question

 Rút gọn 

(x^2+1)(x-3) -(x-3)(x^2+3x+9)

Answer 1

\(=\left(x-3\right)\left(x^2+1-x^2-3x-9\right)\)

\(=\left(x-3\right)\left(-3x-8\right)\)

_Moon_

Answer 2

(x^2+1)(x-3) - (x-3)(x^2+3x+9)

=(x-3)[(x^2+1) - (x^2+3x+9)

=(x-3)(x^2+1-x^2-3x-9)

=(x-3)(-3x-8) = -3x^2-8x+9x+24

=-3x^2+x+24

Answer 3

\(\left(x^2+1\right)\left(x-3\right)-\left(x-3\right)\left(x^2+3x+9\right)\)

\(=\left(x-3\right)\left(x^2+1-x^2-3x-9\right)\)

\(=\left(x-3\right)\left(-3x-8\right)\)