Answer:
The answer is option 2.
Step-by-step explanation:
In the question, 16 and 81 are perfect squares. So in order to find the equivalent equation, you have to factorize it :
APPLY,
[tex](a + b)(a - b) = {a}^{2} - {b}^{2} [/tex]
So for this question :
[tex]16 {x}^{4} - 81 = 0[/tex]
[tex]{(4 {x}^{2})}^{2} - {(9)}^{2}= 0[/tex]
[tex](4 {x}^{2} + 9)(4 {x}^{2} - 9) = 0[/tex]
