Question

$2 {x}^{2} - x - 21$

Answer 1

Answer:

( 2 x - 7 )( x + 3)

Step-by-step explanation:

2 x² - x - 21

We need to apply middle split : Split - x into 6 x - 7 x

                                                     ==> 2 x² + 6 x - 7 x - 21

                                                     [ Taking  common ]

                                                     ==> 2 x ( x + 3 ) - 7 ( x + 3 )

                                                     ==>  ( 2 x - 7 )( x + 3)

The zeroes of the polynomial would be :

( 2 x - 7 )( x + 3 ) = 0

Either :

( 2 x - 7 ) = 0

==> 2 x = 7

==> x = 7 / 2

or :

x + 3 = 0

==> x = -3

Hope it helps you:-)

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