Functions and relations review

1. Functions! It’s a funny name for equations, but we can write and evaluate them!

2. Graphing Points and Functions Graphing points (x, y) X – across, positive right, negative left Y – up and down, positive up, negative down Graph the following points: (3, -1) (3, 2) (3, 5) Graph the following points: (-3, 2) (1, 2) (4, 2) When the x’s are the same, the line is ? When the y’s are the same, the line is ? Answers on the next page!

3. Answers to Graphing Points When the x’s are the same, the line is VERTICAL (straight up and down)! So the equation is x = the number! When the y’s are the same, the line is HORIZONTAL (straight across)! So the equation is y = the number!

4. Functions vs. Relations Relations Any relationship of x and y coordinates. Functions A relationship of x and y coordinates with only 1 y for every x. Function Relation

5. Evaluating Functions To evaluate functions, REPLACE the variable with a number, then use the order of operations! If f(x) = 3x 2 + 2, find f(5). f(5) = 3(5) 2 + 2 f (5) = 3(25) + 2 f(5) = 75 + 2 f(5) = 77 You try! If f(x) = -2x – 5, find f(1).

6. Writing Functions Sometimes, we need to write functions from tables, points, or word problems. What function represents the following situations? A banker gets a $5,000 signing bonus, plus $25 each hour she works. How much money does she make for working h hours? Answers are on the next page!

7. Answers to Writing Functions y = 2x – 7 f(x) = x + 3 y = 25h + 5000 GOOD LUCK ON THE TEST TOMORROW!!!