Question

evaluate the following by using the identity :(x+a)(x+b)

(2x-3) (2x+5)

plz answer fast. I'll mark you the brainliest

Answer 1

$\Longrightarrow{\boxed{\bold{Answer: 4x^2 + 4x - 15}}}$

$\textbf{\underline{Step-by-step explanation :- }}$

$\bold{Since \: we \: know \: that} \\ \\ \bold{ Identity \: (x + a)(x + b) }\\ \\ \bold{ = {x}^{2} + (a + b)x + ab} \\ \\ \bold{ So \: (2x - 3)(2x + 5)} \\ \\ \bold{ = {(2x)}^{2} + ( - 3 + 5)2x + ( - 3)(5)} \\ \\ \bold{ = 4 {x}^{2} + 2 \times 2x - 15} \\ \\ \bold{ = 4 {x}^{2} + 4x - 15 }$

Answer 2

Identity : (x + a) (x + b)

= x^2 + (a + b)x + ab

According to the Question

(2x - 3) (2x + 5)

Substitute the values :-

= (2x)^2 + (-3 + 5)2x + (-3)(5)

= 4x^2 + 2 × 2x - 15

= 4x^2 + 4x - 15