Question

multiply (9x+3)(9x-3)

Answer 1

Answer:

$(9x + 3)(9x - 3) = 81x^2 - 9$

Step-by-step explanation:

Method 1: $a^2 - b^2 = (a - b)(a +b)$

(9x + 3)(9x - 3)

$=(9x)^2 - (3)^2\\= 81x^2 - 9$

Method 2:

(9x + 3)(9x - 3)

= 9x (9x - 3) + 3 (9x - 3)

= 9x (9x) - 9x (3) + 3(9x) - 3(3)

$= 81x^2 - 27x + 27x - 9\\= 81x^2 - 9$

Answer 2

Answer:

The required result will be $(9x+3)(9x-3)=81x^{2} -9$

Step-by-step explanation:

In accordance with the information provided in the question,

Given the data in question  (9x+3)(9x-3)

We have to use the identity (a+b)(a-b)=$a^{2} -b^{2}$

We can write this (a+b)(c-d)

Multiplying a into c with a into d and multiplying b into c with b into d

then we get

$ac+ad-bc-bd$

$(9x+3)(9x-3)$

$(9x\times 9x)+(9x\times 3)-(3\times 9x)-(3\times 3)\\81x^{2} +27x-27x-9$

Therefore, positive 27 and negative 27 are cancel we get,

$81x^{2} -9$

Hence required result will be $(9x+3)(9x-3)=81x^{2} -9$