Question

Factor completely 81x4 − 16.

(3x − 2)(3x − 2)(9x2 + 4)
(3x − 2)(3x + 2)(9x2 − 4)
(3x − 2)(3x + 2)(9x2 + 4)
(3x + 2)(3x + 2)(9x2 + 4)

Answer 1

$(9x^{2} +4)(3x+2)(3x-2)$

Option C

Step-by-step explanation:

Given,

$81x^{4} -16$

To find the factors.

Formula:

$a^{2} -b^{2}= (a+b)(a-b)$

Now,

$81x^{4} -16$

= $(9x^{2} )^{2}-4^{2}$

=$(9x^{2}+4)(9x^{2}-4)$

= $(9x^{2}+4) ((3x)^{2} -2^{2} )$

= $(9x^{2} +4)(3x+2)(3x-2)$

Answer 2

Answer:

It is C

Step-by-step explanation:

Go on photomath, it expalins y