Question

How to Factorise p^4-q^4

Answer 1

$p {}^{2} −q {}^{2} =(p−q)(p+q) p {}^{4} −q {}^{4} \\ =(p {}^{2} −q {}^{2} )(p {}^{2} +q {}^{2} ) \\ =(p−q)(p+q)(p {}^{2} +q {}^{2} )$