Question

factorize the following expression (b+4)^2+4 (b+4)-21​

Answer 1

Step-by-step explanation:

Given, expression (b+4)^2+4 (b+4)-21

= [(b+4)² + 2(b+4)(2) + 2²] - 25

(a+b)² = a² + 2ab + b²

= [(b+4) + (2)]² - 5²

= (b+6)² - 5²

a² - b² = (a+b)(a-b)

= [(b+6) + 5] [(b+6) - 5]

= [b+6+5] [b+6-5]

= ( b + 11 ) ( b + 1 )

Answer 2

Answer:

-1 or -11

Step-by-step explanation:

(b+4)^2 +4(b+4)-21

using:- (a+b)^2 = a^2 + b^2 + 2ab

=[(b^2 + 4^2 + 2(4)(b))] + 4b + 16 -21

=b^2+16+8b+4b+16-21

=b^2+12b+11

=b^2+11b+1b+11

=b(b+11) + 1(b+11)

=(b+1) (b+11)

therefore b= -1 or b= -11