1. FUNCTIONS X Y

2. What is a Function?
Function – a relationship that assigns exactly one output to one input value.
Function Table – organizes the input, output based on the rule.
Function Rule – describes the relationship between input (x) and output (y).
Input (x)
Output (x + 7) 10 12 14
Input (x)
Output (y) 10 17 12 19 14 21
= 17
= 19
= 21

3. Examples
When given the rule, plug in the x input values to find y output values.
Example 1
Example 2
Input (x)
Output (x -4) 4 7 10
Input (x)
Output (2x + 1) 4 7 10 9 3 15 6 21

4. Examples Continued
When given the x input values and the y output values, figure out the rule.
Example 3
Example 4
Input (x)
Output (y) 4 1 16
Input (x)
Output (y) 4 10 8 18 22
Rule: x ÷ 4 = y
Rule: 2x + 2 = y

5. Creating Examples
Choosing a variable to represent the input is called “defining the variable”.
Example 5
A local band charges $70 for each hour it performs. Define a variable, then write a function rule to relate the total charge of performance to the number of hours performed.
Let h represent the number of hours (the cost of performance depends on h).
Determine the rule. When h = 1, y = $70, therefore rule is y=70h.
*In this scenario, h is the independent variable and y is the dependent variable*

6. Real Life Scenario & Practice