Solve the formula for $P$ given $r=-0.05$, $t=1.5$, and $A=21$.
$A=P(1+rt)$

A giant water tank takes the shape of a cylinder. It has a radius of $2$ m and a height of $5$ m. How much water can this tank hold? Round to the nearest tenth of a $m^3$.

Cylinder: $V=\pi r^{2}h$

The weather forecast says it will be $95°F$ today. What is this temperature in $°C$?

$C=\frac{5}{9}(F-32)$

Rearrange the following formula to solve for the indicated variable.

$S=2(x+xz+yz)$

Solve for $y$ .

Rearrange the following formula to solve for the indicated variable.

$T=50+\frac{N-40}{4}$

Solve for $N$.