Example 2A: Identifying Independent and Dependent Variables Identify the independent and dependent variables in the situation. A painter must measure a room before deciding how much paint to buy. Dependent: Independent:

Example 2B: Identifying Independent and Dependent Variables Identify the independent and dependent variables in the situation. The height of a candle decrease d centimeters for every hour it burns. Dependent: Independent:

Example 2C: Identifying Independent and Dependent Variables Identify the independent and dependent variables in the situation. A veterinarian must weight an animal before determining the amount of medication. Dependent: Independent:

Example 3A: Writing Functions Identify the independent and dependent variables. Write a rule in function notation for the situation. A math tutor charges $35 per hour. Dependent: Independent: Function:

Example 3B: Writing Functions Identify the independent and dependent variables. Write a rule in function notation for the situation. A fitness center charges a $100 initiation fee plus $40 per month. Dependent: Independent: Function:

Check It Out! Example 3a Identify the independent and dependent variables. Write a rule in function notation for the situation. Steven buys lettuce that costs $1.69/lb. Dependent: Independent: Function:

Check It Out! Example 3b Identify the independent and dependent variables. Write a rule in function notation for the situation. An amusement park charges a $6.00 parking fee plus $29.99 per person. Dependent: Independent: Function:

Example 4A: Evaluating Functions Evaluate the function for the given input values. For f(x) = 3x + 2, find f(x) when x = 7 and when x = –4. f(x) = 3(x) + 2 f(x) = 3(x) + 2

Example 4B: Evaluating Functions Evaluate the function for the given input values. For g(t) = 1.5t – 5, find g(t) when t = 6 and when t = –2. g(t) = 1.5t – 5 g(t) = 1.5t – 5

Example 4C: Evaluating Functions Evaluate the function for the given input values. For , find h(r) when r = 600 and when r = –12.

Check It Out! Example 4a Evaluate the function for the given input values. For h(c) = 2c – 1, find h(c) when c = 1 and when c = –3. h(c) = 2c – 1 h(c) = 2c – 1

Check It Out! Example 4b Evaluate each function for the given input values. For g(t) = , find g(t) when t = –24 and when t = 400.

Example 5: Finding the Reasonable Range and Domain of a Function Joe has enough money to buy 1, 2, or 3 DVDs at $15.00 each. Write a function to describe the situation. Find a reasonable domain and range of the function. f(x) = • x

Example 5 Continued Substitute the domain values into the function rule to find the range values. x f(x) A reasonable range for this situation is: