1. Then/Now You found rates of change and slopes. (Lesson 3–3) Write and graph linear equations in slope-intercept from. Model real-world data with equations in slope-intercept form.

2. Vocabulary slope-intercept form

3. Concept

4. Example 1 Write and Graph an Equation Write an equation in slope-intercept form of the line with a slope of and a y-intercept of –1. Then graph the equation.

5. Now graph the equation. Example 1 Write and Graph an Equation Step 1Plot the y-intercept (0, –1). Step 2The slope is. From (0, –1), move up 1 unit and right 4 units. Plot the point. Step 3Draw a line through the points. Answer:

6. A.A B.B C.C D.D Example 1 Write an equation in slope-intercept form of the line whose slope is 4 and whose y-intercept is 3.

7. Example 2 Graph Linear Equations Graph 5x + 4y = 8. Solve for y to write the equation in slope-intercept form.

8. Example 2 Graph Linear Equations Slope-intercept form Step 1Plot the y-intercept (0, 2). Now graph the equation. From (0, 2), move down 5 units and right 4 units. Draw a dot. Step 2The slope is Step 3Draw a line connecting the points. Answer:

9. A.A B.B C.C D.D Example 2 Graph 3x + 2y = 6.

10. Example 3 Graph Linear Equations Graph y = –7. Step 1Plot the y-intercept (0,  7). Step 2The slope is 0. Draw a line through the points with the y-coordinate  7. Answer:

11. A.A B.B C.C D.D Example 3 Graph 5y = 10.

12. Example 5 Write and Graph a Linear Equation B. Graph the equation. The graph passes through (0, 117) with a slope of