Solve Qs=80+20P.E

$$Q s = 80 + 20 P . E$$

Solve for P

$$P=\frac{Qs-80}{20}$$

Steps for Solving Linear Equation

Swap sides so that all variable terms are on the left hand side.

$$80+20P=Qs$$

Subtract 80 from both sides.

$$20P=Qs-80$$

Divide both sides by 20.

$$\frac{20P}{20}=\frac{Qs-80}{20}$$

Dividing by 20 undoes the multiplication by 20.

$$P=\frac{Qs-80}{20}$$

Divide Qs-80 by 20.

$$P=\frac{Qs}{20}-4$$

Solve for Q

$$\left\{\begin{matrix}Q=\frac{20\left(P+4\right)}{s}\text{, }&s\neq 0\\Q\in \mathrm{R}\text{, }&P=-4\text{ and }s=0\end{matrix}\right.$$

Steps for Solving Linear Equation

The equation is in standard form.

$$sQ=20P+80$$

Divide both sides by s.

$$\frac{sQ}{s}=\frac{20P+80}{s}$$

Dividing by s undoes the multiplication by s.

$$Q=\frac{20P+80}{s}$$

Divide 80+20P by s.

$$Q=\frac{20\left(P+4\right)}{s}$$