Question

factorise x3-23x2+142x-120

Answer 1

$\bold \red{x^3−23x^2+142x−120}$

$\bold\green{=x^3−x^2−22x^2+22x+120x−120}$

$\bold \blue{=x^2(x−1)−22x(x−1)+120(x−1)}$

$\bold \pink{=(x−1)(x^2−22x+120)}$

$\bold \purple{{{{{{=(x−1)[x^2−10x−12x+120]}}}}}}$

$\bold \green{=(x−1)[x(x−10)−12(x−10)]}$

$\bold \pink{=(x−1)(x−10)(x−12)}$