Vector Algebra question bank (Mathematics)

If $|\bar{a}|=3, |\bar{b}|=4, |\bar{a}-\bar{b}|=5$,then $|\bar{a}+\bar{b}|=$

The sum of the lengths of projections of $p \hat{i} + q \hat{j} + r \hat{k}$ on the coordinate axes, where $p = 4, q = -5, r = 7$, is: (in $\text{ units}$)