Question

Factorise this 81a4 - b4​

Answer 1

Answer:

$81 {x}^{4} - {y}^{4} = \\ {x}^{2} - {y}^{2} = (x + y)(x - y) \\( 9 {x}^{2} - {y}^{2}) (9 {x}^{2} + {y}^{2} ) = ans \:$