For each of the following, perform the indicated operations on the vectors

$\vec a = 2\,\mathit{\vec j}+3\,\mathit{\vec k}$, $\vec b = -3\,\mathit{\vec i}+3\,\mathit{\vec j}+5\,\mathit{\vec k}$, $\vec z = 4\,\mathit{\vec i}+3\,\mathit{\vec j}$.

(a) $4 \vec a + 2 \vec b =$

(b) $5 \vec a + 4 \vec b - 4 \vec z =$