Question

use identities to factorise each of the following​

Answer 1

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

$\: \: \: \: 4 - 9 {x}^{4} \\ = {(2)}^{2} - ( { {3x}^{2} )}^{2} \\ = (2 + 3 {x}^{2} )(2 - 3 {x}^{2} )$