How could I reason that $P=V^2 \div R$ because $P = iV$ and $V=iR$?

Question

I'm trying to teach myself simple electronic formulas. I haven't done algebra in awhile, and I'm very rusty.

I know that $P = iV$, and $V = iR$, therefore, $P = i^2R$.

How could I figure out that $P = V^2 \div R$, because I know $P = i^2R$?

Is there a name for the trick used? I would like to find out more about it.

Answer 1

I realized that since current equals voltage divided by resistance, IE $i=V \div R$.

$P=i^2R = (V \div R)^2 R = V^2\div R$