Answer
(a) $2i$
(b) $-\sqrt 3k$
(c) $\dfrac{3}{10}j+\dfrac{2}{5}k$
(d) $6j-2j+3k$
Work Step by Step
Need to find parts a,b,c,d as follows:
(a) $2(i)=2i$
(b) $\sqrt 3(-k)=-\sqrt 3k$
(c) $\dfrac{1}{2}(\dfrac{3}{5}j+\dfrac{4}{5}k)=(\dfrac{3}{10}j+\dfrac{4}{10}k)=\dfrac{3}{10}j+\dfrac{2}{5}k$
(d) $7(\dfrac{6}{7}i-\dfrac{2}{7}j+\dfrac{3}{7}k)=6j-2j+3k$
