1. Using Formulas and Literal Equations
Section 3.6 Solve literal equations for a specific variable and use formulas to solve problems.

2. Literal Equation: An equation that involves two or more variables.
Formula: A literal equation that states a rule for a relationship among quantities.
Examples:
C = (F – 32) A = P + I
A = lw P = 2l + 2w
D = rt C = np
y = mx + b C = 2πr
A = ½h(b₁ + b₂) D =

3. Example: Find the area of the trapezoid by using the formula A = ½h(b₁ + b₂), if h = 5, b₁ = 6, and b₂ = 9. b₁ h b₂

4. C = (F – 32) Degrees Celsius Degrees Fahrenheit
Example: Convert each temperature from degrees Fahrenheit to degrees Celsius
a. 68°F b. 32°F c. 23°F
Practice: P147 Try this after Example 1

5. Example: Louis has 480 feet of chicken wire and is building a pen
Example: Louis has 480 feet of chicken wire and is building a pen. He wants the length of the pen to be 3 times the width. Find the dimensions of the pen.
Practice: P151 # 11

6. Example: The area of a trapezoid is 90 square inches
Example: The area of a trapezoid is 90 square inches. The height of the trapezoid is 12 inches. The longer base is 9 inches. Use the formula for the area of a trapezoid, A = ½h(b₁ + b₂), to find the length of the shorter base.
Practice: P151 # 12

7. Example: Use the formula C = 2πr to find the value of r for the given circumference. Use 3.14 for π.
Practice: P151 # 13

8. Example: Solve for the indicated variable d = k + s for s
r = for d
y = mx + b for m
p = 6x + 2z for z
Practice: P 151 #’s 8-10
Homework: P #15-51 (by 3s)