Question

factorise 81x^2 - 1​

Answer 1

this is the answer for your question

Answer 2

Answer:

$\: \: \: \: \: 81 {x}^{2} - 1$

$= {(9x)}^{2} - {(1)}^{2}$

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

Here, a = 9x and b = 1

$\: \: \: \: \:( 9 {x})^{2} - {(1)}^{2}$

$= (9x + 1)(9x - 1)$