Question

Use identity to solve:
(-9x+ 3) (-9x - 5)​

Answer 1

(-9x+ 3) (-9x - 5)​

=($-9x^{2}$) +(3+(-5)-(9x+3)(-5)

=$81x^{2}$ +(-2)-9x+(-15)

by using formula

(x+a) (x+b) =$x^{2}$+(a+b)x+ab

= 81$x^{2}$ + 18x -15

Answer 2

Answer:

$(-9x+3)(-9x-5)=81x^{2}+18x-15$.

Step-by-step explanation:

Given product is $(-9x+3)(-9x-5)$.

It is in the form $(x+a)(x+b)$.

We are asked to find the product using an identity.

We know the identity for these kind of problems,

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

On comparing both the equations, we get the corresponding values.

Here in the given problem,

$x=-9x,a=3,b=-5$.

On substituting these values in the identity, we get

$(-9x+3)(-9x-5)=(-9x)^2+(3+(-5))(-9x)+3(-5)$

Expanding these values, we get

$=81x^2+(-2)(-9x)-15$

$=81x^{2}+18x-15$

The resulting equation of the product is $81x^{2}+18x-15$.