Algebra 1 / Unit 2: Solving Equations
2.4 Literal Equations and Formulas
Notes
A literal equation has more than one variable. Solve for one variable by treating the others like numbers.
- Solve $A = lw$ for $w$: $\displaystyle w = \frac{A}{l}$.
- Solve $y = mx + b$ for $x$: $y - b = mx$, so $\displaystyle x = \frac{y - b}{m}$.
- Use the same inverse operations as always.
Practice
Solve $P = 2l + 2w$ for $w$.
Subtract $2l$, then divide by 2.
Solve $d = rt$ for $t$.
Divide both sides by $r$.
The formula $\displaystyle F = \frac{9}{5}C + 32$ converts Celsius to Fahrenheit. Solved for $C$:
Subtract 32, then multiply by $\displaystyle \frac{5}{9}$.
Ready for more? Take the Unit 2 test.