## Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)

$-j$
Let us consider two vectors $v=pi+qj$ and $w=xi+yj$, then we have: $v \pm w=(p \pm x)i+(q \pm y)j$ The magnitude of any vector (let us say $v$) can be determined using the formula $||v||=\sqrt{p^2+q^2+r^2}$ Therefore, $2v +3w= (6i-10j) +(-6i+9j) \\ = 6i-10j -6i+9j \\ = -j$