Question

SOLVE

(x2-4x)(x2-4x-1)-20

Answer 1

HEY!!

x2 4x) (x2 4x 1) 20

Putx2 4x=t

⇒ (x2 4x) (x2 4x 1) 20 =t(t 1) 20 =t2t 20 =t2 5t+ 4t 20

=t(t 5) + 4 (t 5) = (t+ 4) (t 5)

= (x2 4x+ 4) (x2 4x 5)

= (x2 2x 2x+ 4) (x2 5x+x 5)

= [x(x 2) 2 (x 2)] [x(x 5) + 1 (x 5)]

= (x 2) (x 2) (x+ 1) (x 5)

Answer 2

Hey Friend ☺

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

Let ( x^2 - 4x ) = a

( a )( a - 1 ) - 20

= a^2 - a - 20

= a^2 - 5a + 4a - 20

= a ( a - 5 ) + 4 ( a - 5 )

= ( a - 5 )( a + 4 )

Substitute value of a

= ( x^2 - 4x - 5 )( x^2 - 4x + 4 )

= ( x^2 - 5x + x - 5 )( x^2 - 4x + 4 )

= [ x ( x - 5 ) + 1 ( x - 5 )] ( x^2 - 4x + 4 )

= ( x - 5 )( x + 1 )( x^2 - 4x + 4 )

= ( x - 5 )( x + 1 )( x + 2 )^2


= ( x - 5 )( x + 1 )( x + 2 )( x + 2 )

Hope it helps you ..!!

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