Question

Factorise the following using suitable identities:
$a^4-{16b}^4$

Answer 1

$a^4-16b^4$

$=a^4-{\left(2b\right)}^4$

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

$=(a-2b)(a+2b)(a^2+4b^2)$