Math-8 NOTES DATE: ______/_______/_______ What: function tables Why: To identify the “function rule” from a table, and explore the independent v. dependent variables in a function table. What: function tables Why: To identify the “function rule” from a table, and explore the independent v. dependent variables in a function table. NAME: review points: Remember, a _______________________________ is a group of ordered pairs, and a ______________________________________ is a special TYPE of relation. Basically, a FUNCTION represents a specific relationship between the “x” and “y” variables. Do you remember ? Fill in below table: xy INPUT RANGE INDEPENDENT So, we already know how to identify a function (the “x” value can not repeat), but what does it mean??? Again, it comes down to identifying the _____________________________________ between the x and y variables– between the ________________________________ and dependent variables (the input and the output). Sometimes it’s helpful to think of functions as a _______________________________ because the “input” numbers in a function table result in the __________________________ numbers. The trick is to find out what is being done to the input number in order to yield the output number– this is the ______________________________________________. Function Machine Manipulative The function “Machine”: Input Output Play a game of “Guess my Rule”...

Identifying the “rule” from a table: 1) Rule/Equation: _______________ 2) Rule/Equation: _______________ 3) Rule/Equation: _______________ 4) Rule/Equation: _______________ 5) Rule/Equation: _______________ 6) Rule/Equation: _______________ xy y = 3x xy xy xy xy xy what does this have to do with real-life situations? All of the above function tables could represent real-life situations. Why? Because, in life, there are many outcomes that ____________________________ on what we put into them. (Input/ Output– Independent/ Dependent)

Independent v. dependent variables: Situation Independent (x) Dependent (y) Equation 1) The taxi cab company charges a $5.00 flat fee plus $.50 for every mile driven. Number of miles driven Amount of $ charged per taxi ride y = x 2) Jeff makes $12 per hour at the mall and gets paid weekly. 3) The lawn –mowing company charges $40 per yard, plus $15 for each acre that needs mowed. 4) The Circumference of a circle is found by multiplying the radius times twice π. (C= 2πr ) 5) The cell phone company charges a flat fee of $50 for the first 1,000 minutes each month, plus $.05 for every additional minute. Poster lab... (wait for directions)

Guess my Rule DATE: ______/_______/_______ NAME:__________________________ Input Output

DATE: ______/_______/_______ NAME:__________________________

Math-8 PRACTICE DATE: ______/_______/_______ NAME:__________________________ “ Function tables” Input Output 1) Rule/Equation: ___________________ 2) Rule/Equation: ___________________ 3) Rule/Equation: ___________________ 4) Rule/Equation: ___________________ 5) Rule/Equation: ___________________ 6) Rule/Equation: ___________________ 7) Rule/Equation: ___________________ 8) Rule/Equation: ___________________ 9) Rule/Equation: ___________________ xy xy xy xy xy xy Fill in the missing information, and write the equation/rule for each of the following tables: xy xy xy

Math-8 PRACTICE DATE: ______/_______/_______ NAME:__________________________ “ independent v. dependent” SituationIndependent (x) Dependent (y) Equation 1) You charge $10 per hour for babysitting. # of hours you babysit Amount of $ you will make y = 10x 2) Jake charges $40 per lawn for his neighborhood lawn service. 3) You buy a certain # of shirts for $19.99 each, plus a pair of jeans for $30. 4) The Area of a rectangle is found by multiplying the length times the width. 5) The propane company charges a flat fee of $10 per month, plus $4.50 per gallon used. 6) Your new Honda gets 32 miles per gallon, meaning you can drive 32 miles for every gallon of gas in your tank. 7) Eric drove an average of 55 miles per hour on his trip to visit family. 8) The Area of a circle is found by multiplying π times the radius squared. 9) Jane weighed 160 lbs. at her heaviest. She has been losing an average of 2 lbs. per month for the last year. How much does she weigh now? 10) The sunflower has been growing an average of 4 inches per week. Its maximum height will be 36 in. tall. Identify the Independent/ Dependent variables. Then, write the equation: