Question

(x^2-4x)(x^2-4x-1)-20

Answer 1

Final Answer :
${(x - 2)}^{2} (x - 5)(x + 1)$

Steps:
1)
$( {x }^{2} - 4x)( {x }^{2} - 4x - 1) - 20 \\ = > {( {x}^{2} - 4x)}^{2} - ( {x }^{2} - 4x) - 20$

Let
$t = {(x}^{2} - 4x)$

2)
${t}^{2} - t - 20 \\ (t - 5)(t + 4) \\ = > ( {x}^{2} - 4x - 5)( {x}^{2} - 4x + 4) \\ = > (x - 5)(x + 1) {(x - 2)}^{2}$

Answer 2

Answer:

Step-by-step explanation:

(x²-4x)(x²-4x-1)-20

=x⁴-4x³-x²-4x³+16x²+4x-20

=x⁴-8x³+15x²+4x-20