Question

Factorise

4x²-y²+6y-9

Answer 1

®4 x^2 - y^2 + 6 y - 9

=4 x^2 - ( y^2 - 6y + 9 )

=4 x^2 - ( y^2 - 2 ( y ) ( 3 ) + ( 3 )^2 )

=( 2 x )^2 - ( y - 3 )^2

use identity :

a^2 - b^2 = ( a - b ) ( a + b )

therefore ,

(2 x )^2 - ( y - 3 )^2

={ 2x - ( y - 3 ) } { 2x + ( y - 3 ) }

=( 2x - y + 3 ) ( 2x + y - 3 )

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| : hope helps : |
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