Answer:
[tex](9x+2)(9x-2)[/tex]
Last option is correct.
Step-by-step explanation:
The given expression is [tex]81x^2-4[/tex]
Write the expression in perfect squares
[tex](9x)^2-2^2[/tex]
Apply the difference of squares formula: [tex]a^2-b^2=(a+b)(a-b)[/tex]
Here, a = 9x, b = 2
[tex](9x)^2-2^2\\\\=(9x+2)(9x-2)[/tex]
Therefore, the factored form is [tex](9x+2)(9x-2)[/tex]
Last option is correct.
