Question

factorise the following

Answer 1

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

Answer 2

${a}^{2} - {(b - c})^{2}$

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

$= {a}^{2} - {b}^{2} - {c}^{2} + 2bc$