Question

a(a+b-c)+b(b+c-a)+c(c+a-b)​

Answer 1

${{a}^{2} + ab - ac + {b}^{2} + bc - ab + {c}^{2} + ac - bc}$

$\: \: \: \: \: \: \: \: = > {a}^{2} + {b}^{2} + {c}^{2}$