Question

Simplify:
(1+m+n)2 + (1 -m+n)2​

Answer 1

we have equation

${(l + m + n)}^{2} + {(l - m + n)}^{2} \\ {l}^{2} + {m}^{2} + {n}^{2} + {l}^{2} - {m}^{2} + {n}^{2} \\ 2 {l }^{2} + 2 {n}^{2} \\ 2( {l}^{2} + {n}^{2} ) = 0 \\ now \: we \: can \: write \: it \\ {(l + n)}^{2} = 0$