1. Math Unit 5 Section 6.7

2. A literal equation is an equation that contains more than one variable.
Examples: 2x + 3y = 6
4w – 2x + z = 7
Many formulas are literal equations.
A = l w
V = lwh
To solve a literal equation, use equation solving techniques to rearrange the equation until the desired variable is alone on one side of the equation.

3. Objective: To solve a literal equation
Solve for y:
3x – 4y = 12
Subtract 3x from both sides
-4y = 12 – 3x
Divide both sides by -4
y = 12 – 3x
The answer can be rearranged if desired
y = 3x –

4. Objective: To solve a literal equation
Solve for x:
5x – 2y = 10
Add 2y to both sides
5x = y
Divide both sides by 5
x = y
The answer can be rearranged if desired 2y
x =
+ 2 5

5. Objective: To solve a literal equation
Solve for R:
I =
Multiply the equation by (R + r) to clear any fractions E
(R + r)
R + r
IR + Ir = E
Subtract Ir from both sides
IR = E – Ir
Divide both sides by I
R = E – Ir I

6. Objective: To solve a literal equation
Solve for c:
L = a(1 + c)
Simplify the right side by multiplying
L = a + ac
Subtract a from both sides
L – a = ac
Divide both sides by a
c = L – a a

7. Objective: To solve a literal equation
Solve for C:
S = C – rC
Factor the right side
S = C(1 – r)
Divide both sides by (1 – r)
C = S – r