FUNCTIONS X Y

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 10 + 7 = 17 12 + 7 = 19 14 + 7 = 21

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

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

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*

Real Life Scenario & Practice http://studyjams.scholastic.com/studyjams/jams/math/algebra/function-tables.htm