Question

Use the identity (x + a) (x + b) = x2 + (a + b) x + ab, to find the product of the following:

(4x + 9) (4x + 12)​

Answer 1

Answer:

( 4x + 9 )(4x + 12 )

16x^2 + 84x + 108

(4x)^2 + ( 9 + 12 )4x + (12)(9)

Answer 2

$\huge\green{\textbf{\textsf{Question}}}$

$\sf Using \: the \: identity : \\ \bf (x + a)(x + b) = {x}^{2} + (a + b)x + ab \\ \sf find \: the \: product \: of : \\ \bf (4x + 9)(4x + 12)$

$\huge\green{\textbf{\textsf{Answer}}}$

$\bf (4x + 9)(4x + 12) \\ \sf Here \: \: x = 4x \: , \: \: \: \: a = 9 \: ,\: \: \: \: b = 12 \\ \bf = (4x)^{2} + (9 + 12)4x + (9 \times 12) \\ \bf = {16x}^{2} + (21)4x + (108) \\ \bf = \underline{ \underline{{16x}^{2} + 84x + 108}}$

$\huge \green{\textbf{\textsf{Hope \: it \: helps..!!}}}$