Question

Find u*v if u=14j and v=i+4j

Answer 1

$\vec{u}$ and $\vec{v}$ are vectors and:

 $\vec{u}=14j=0i+14j=[0,14]\\\\ \vec{v}=i+4j=1i+4j=[1,4]$

$\vec{u}\cdot\vec{v}$ is the dot product or scalar product, so:

$\vec{u}\cdot\vec{v}=[0,14]\cdot[1,4]=0\cdot1+14\cdot4=56$

Correct answer is A.