Geometric Representations of Complex Numbers Practice Test

A complex number $w=-1-4i$ is plotted on the complex plane with coordinates $(a,b)$ corresponding to $a+bi$. What are the coordinates of the point for $w$, and what is the modulus $|w|=\sqrt{a^2+b^2}$?

Plotting complex numbers uses the point $(a,b)$ to represent $a+bi$ on the complex plane. If $z=2+i$, what complex number corresponds to the point obtained by multiplying by $i$ (i.e., $iz$), and what geometric transformation does this represent?