Math 8: Functions Section #3: Writing Rules to Represent Functions Corresponds with Module 5, Lesson 6, 8.F.4 Notes #62 ____________________________ Function: a set of _________________ in which each _____________ value (x-value/domain) corresponds to one and only one ______________ value (y-value/range). Linear Function: a function with a constant ________________________ between the ordered pairs and whose graph forms a _______________________. Example#1: This represents a function expressed in table form. Look for a pattern or relationship between the x and y values to express the data in a variety of ways. x y -2 -1 -1 0 0 1 1 2 2 3 Verbally: ____________________________________ Algebraically (Rule): __________________________ Graphically: _________ each point and draw a line. You Try: For each set of data, express the relationship verbally and find the rule that relates x to y. 1) x y 0 0 2 6 4 12 6 18 8 24 Rule: ____________________ Verbally: ________________________________________________________________________ 2) x -2 -1 0 1 2 y -5 -4 -3 -2 -1 Rule: ____________________ Verbally: ________________________________________________________________________ x y 3) -6 3 -2 1 2 -1 6 -3 10 -5 Rule: ____________________ Verbally: ________________________________________________________________________ Example#2: Find the rule for this function. x y 0 2 1 4 2 6 3 8 4 10 To Find the Rule for a Function: 1) Look for an _______________ pattern that can be expressed ______________. 2) If you can’t find a pattern, then think of ___________________. 3) Find the ____________________ or _________. = change in the change in the 4) Find the ________________, by substituting in the ___, ___, & ___ values into y = mx + b and solving for _____. YOU TRY: Write a rule that defines the function algebraically. 4) x y 5) x y -2 -7 2 6 -1 -4 4 9 0 -1 6 12 1 2 8 15 2 5 10 18 Rule: ____________________ Rule: ____________________ Math 8: Functions Section #3: Writing Rules to Represent Functions Corresponds with Module 5, Lesson 6, 8.F.4 HW #62 ____________________________ 1-4 Write a rule that defines each function algebraically. 1) 2) x y x y -2 -10 -2 -7 -1 -5 -1 -2 0 0 0 3 1 5 1 8 2 10 2 13 x y 4) x y 3 -1 5 6 0 10 5 9 1 15 6 12 2 20 7 15 3 25 8 3) 4 Write a rule that defines each function algebraically. Find the missing values. 5) 6) x y x y 1 4 -4 3 2 12 -2 1 3 20 0 -1 3 6 76 -9