1. Writing Linear Functions in Slope-Intercept Form

2. Review In the equation y = mx + b, what is m? what is b? So, if you were given a slope of -3 and a y- intercept of 5, how would you write the equation of the line?

3. Extra Problems 1. Slope = 8; y-intercept = -7 2. Slope = ¾; y-intercept = -3

4. Write an equation of the line shown. Step 1: What is the slope? Step 2: Write an equation of the line. The line crosses the y-axis at (0,-4). So the y-intercept is what? y = mx + b y = 1x - 4

5. Writing functions Recall that the graphs of linear functions are lines. You can use slope-intercept form to write a linear function. f Earlier in the year, you saw that f (x) = y Now we’re going to take this concept and take it a step further!

6. Example 1 Write an equation for the linear function f with the values f (0) = 5 and f (4) = 17. f f Step 1: Look at f (0) = 5. Doesn’t it look very similar to f (x) = y???? Step 2: What is x and what is y? x = 0y = 5 Step 3: Now put those two into an ordered pair! (0,5) NOW, put the other value into an ordered pair.

7. Continuing on…. Now that you have two points. Find the slope. (0,5)(4,17) m = 3 Now, look at those two points. Does one of them look like they could be the y-intercept? Finally, write an equation of the line with the slope you found and the y-intercept you were given. y = 3x + 5

8. More examples Write an equation for the linear function f with the given values f (0) = -2 f (8) = 4 f (-3) = 6 f (0) = 5 Slope m = ¾ Slope m = -1/3 y-intercept b = -2 y-intercept b = 5

9. Homework In the book: In the book: Pg. 286 #18-38 evenPg. 286 #18-38 even