Question

| 6. factorise in cosing suitable identities) -
à a4- 16b4. b) (a+b)3-(a - b)3​

Answer 1

${a}^{4} - {16b}^{4} \\ \\ {( {a}^{2} )}^{2} - { ({4b}^{2} )}^{2} \\ \\ ({a}^{2} - {4b}^{2})( {a}^{2} + {4b}^{2}) \\ \\ (a + 2b)(a - 2b)( {a}^{2} + {4b}^{2} )$

$\\ \\ \\ {(a + b)}^{3} - {(a - b)}^{3} \\ \\ [(a + b) - (a - b)][ {(a + b)}^{2} + {(a - b)}^{2} + (a + b)(a - b)] \\ \\ [a + b - a + b][( {a}^{2} + {b}^{2} + 2ab) + ({a}^{2} + {b}^{2} - 2ab) + ( {a}^{2} - {b}^{2} )] \\ \\ [2b][{a}^{2} + {b}^{2}+ 2ab+{a}^{2} + {b}^{2} - 2ab + {a}^{2} - {b}^{2}] \\ \\ [2b][ {3a}^{2} + {b}^{2} ]$