Answer:
(9x+7)(9x-7)
Explanation:
We have given an expression.
81x²-49
We have to use difference formula which is given in question.
a²-b² =(a+b)(a-b)
We have to write given expression in above formula.
81x²-49 = (9x)²-(7)²
Using given formula , we have
81x²-49 = (9x+7)(9x-7)
Hence, the factors of given expression are (9x-7) and (9x+7).