Section 5-4 Writing a Function Rule TPI 22A: produce an equation to describe the relationship between data sets Objective: Write a function rule given a table or a real world situation. look for a pattern relating the independent (x) and dependent (y) values Analyze a Table of Values to Write a Function Rule xy What can you do to 1 to get 5? Add 4 to the x value What can you do to 2 to get 6? Add 4 to the x value What can you do to 3 to get 7? Add 4 to the x value Function Rule: f(x) = x + 4
A rule for the function is: Write a rule for the following table of values: What can you do to 1 to get 2? Writing a Function Rule xy What can you do to 2 to get 5? What can you do to 3 to get 10? What can you do to 4 to get 17? f(x) = x 2 + 1
The journalism class makes $25 per page of advertising in the yearbook. If the class sells n pages, how much money will it earn? a. Write a function rule to describe this relationship. Real-world and Function Rules (n) # pages f(x) $ Earned $25 1 $50 2 $75 3 $100 4 Fill the table with data from the problem What do you do to the first value to get the second? Multiply by 25 Write a function rule. f(x) = 25n b. If the class sells 10 pages, how much money will they earn? f(10) = 25 (10) = $250