Question

Add : l^2+m^2+m^2+n^2+n^2+l^2

Answer 1

$\huge{\mathcal{\blue{\underline{Answer}}}}$

$= l {}^{2} + m {}^{2} + m {}^{2} + n {}^{2} + n {}^{2} + l {}^{2} \\ = 2l {}^{2} + 2m {}^{2} + 2n {}^{2}$