Write a function rule given a table or a real-world situation

Let’s write a function rule given a table Ask yourself this question: “What can I do to the x value to get the y value?” Example 1a: Write a function rule for the table. What can I do to _____ to get _____? xy y = x + 6 Add six to each x value

Example 1c: Write a function rule for this table. What can I do to ____ to get ____? xy Square each x value

Example 1b: Write a function rule for this table. What can I do to _____ to get ____? xy

Example 1d: Write a function rule for the table. What can I do to ____ to get ____? x y y = x + 4 Add 4 to each x

Check Understanding: Write a function rule for each table. xF(x) XY y = x - 2 y = 2x

Function Machine Activity Partner up someone near you. Person 1 will think of a function, but keep it secret. Person 2 will give person 1 input values and then try to guess what the function is. InputOutput

Now let’s write a function rule given a real-world situation! Example 2 – Write a function rule for each situation. a. Find the total cost t(c) of c ounces of gummy worms if each ounce costs $.79. t(c) =.79c b. Find the worker’s earnings e(n) for n hours when the worker’s hourly wage is $6.37. c. Find the total distance d(n) traveled after n hours at a constant speed of 45 miles per hour. (d = rt)

d. Find the length l(w) of a box that is two more than four times the width w. e. Find the value of v(q) of a pile of quarters. f. Find the area A(n) of a square when you know the length n of a side. ( A = s 2 ) g. Find the volume V(n) of a cube when you know the length n of a side. (V = lwh)

Example 3a The yearbook class makes $25 per page of advertising in the yearbook. If the class sells n pages, how much money will it earn? If the class sold 6 pages of advertising, how much money did the class make? Don't forget to buy your yearbook! $60 now until January 1

Example 3b The local DJ spent $100 producing cds of her last performance and will sell the cds for $5.50 each. Write a function rule to describe the DJ’s profit as a function of the number of tapes sold.

Example 3c: Suppose you borrow money from a relative to buy a lawn mower that costs $245. You charge each customer $18 to mow a lawn. Write a rule to describe your profit as a function of the number of lawns mowed. How many lawns would you have to mow before you would begin making a profit?

Check Understanding 1. At a supermarket salad bar, the price of a salad depends on its weight. Salad costs $.19 per ounce. Write a function rule to describe the function. How much would an 8-ounce salad cost?

2. Celine wants to buy plain balloons and personalize them with her name to promote her campaign for class president. Each plain balloon costs $.07. Personalizing costs an initial setup fee of $27.00 plus $.13 for each plain balloon that is imprinted. Write a function rule to show the total cost of Celine’s personalized campaign balloons. If Celine personalizes 250 balloons, how much would she spend? T(b) = b +.13b = b T(25) = $77