Question

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

Answer 1

X^2-4x(1*-1)-20
-x^2+4x-20

Something wrong in the question I guess

Answer 2

Answer:

Step-by-step explanation:

(x² - 4x )(x² -4x -1) -20

let (x² -4x ) = P

P(P -1) -20

P² -P -20

P² -5P +4P -20

P( P -5) +4 ( P -5)

(P +4 )( P -5)

put P = x² - 4x

(x² -4x +4)( x² - 4x -5)

(x -2)²( x + 1)(x -5)