1. find a single vector equal to the following

a) $\displaystyle -3(4,-9)-9(2,3)$

b) $\displaystyle \frac{-1}{2}(6,-2)+\frac{2}{3}(6,15)$

2. given $\displaystyle \vec{x} = 2\vec{i}-\vec{j} and \vec{y}=\vec{-i}+5\vec{j}$ find a vector equivalent to each of the following

a) $\displaystyle 3\vec{x}-\vec{y}$

b) $\displaystyle 2(\vec{x}+3\vec{y})-3(\vec{y}+5\vec{x})$