Factorize
$(l+m)^{2}-(l-m)^{2}$

Given:$(l+m)^{2}-(l-m)^{2}$

To do: Factorize the expression

Solution: 

 $(l+m)^{2}-(l-m)^{2}$

=$l^{2}+m^{2}+2lm-l^{2}+m^{2}-2lm$

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

=$2(l^{2}+m^{2})$

Therefore after factoring $(l+m)^{2}-(l-m)^{2}$ we get 

$2(l^{2}+m^{2})$