Question

Solve (l+m + l-m)
And
(l+m - l-m)

Answer 1

$(l + m + l - m) = \\ 2l \\ \\ \\ (l + m - l - m) = \\ 0$

HOPE IT HELPS

Answer 2

(l+m + l-m) = 2l
And
(l+m - l-m) = 0