I. Formulas /solving-literal-equations-for.html">Literal Equations & Formulas
A. A literal equation is an equation with more than one variable .
B. A formula is a literal equation ex pressing an application .
II. Solving Literal Equations
A. Procedure
1. Isolate the term that contains the variable that you
wish to solve for by using
the Addition Property .
2. Isolate the variable that you wish to solve for by
using the Multiplication
Property.
B. Examples - Solve for the specified variable.
1. I = prt; Solve for r
The variable term that contains the variable that we want to solve for is
already isolated on the right side, so we can move on to the next step . We
isolate the r on the right side by dividing both sides by pt:
Answer:
2. P = a + b + c; Solve for b
We will subtract both a & c from both sides to isolate b on the right:
P − a − c = a − a + b + c − c
OR
Answer: b = P − a − c
3. Ax + By = C; Solve for y
We begin by subtracting Ax from both sides to isolate the By term:
Ax − Ax + By = C − Ax
OR
By = C − Ax
Now we divide both sides by B to isolate y on the left side:
Answer: 
4. Now you try one: A = p + prt; Solve for r
Answer: 
5. Solve 
for R.
Even though this is a literal equation, we still approach
it the same way. We
begin by multiplying both sides by the LCD :
S(1 − R) = A − RL
Now we distribute on the left side:
S − SR = A − RL
We now need to get all the terms with "R" in them on one side. Let's do that
by adding RL to both sides:
S + RL − SR = A
Now we need to get all the "R" terms isolated on the left side by subtracting S
from both sides:
RL − SR = A − S
We notice that R is the GCF on the left , so we factor it out to get:
R(L − S) = A − S
Now divide both sides by what R is multiplied by, (L − S):
Answer: 
6. Now you try one: Solve
for z.
Answer: 
7. Solve 
for a.
First, we need to clear the fractions by multiplying both
sides by the LCD, in
this case that is a(a − c). We get:
ab = d(a − c) Distribute
ab = ad − dc Subtract ad from both sides to get all the "a" terms together.
ab − ad = −dc Factor out the GCF on the left side.
a(b − d) = −dc Divided both sides by (b - d) to isolate a.
Answer: 
8. Now you try one: Solve
Answer: 
