Question

a²-[b²-{c²-(a²)}] simplify it

Answer 1

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