1. 1.3/1.4 Linear Equations, Direct Variation and Proportion Warm-up (IN) Learning Objective: to write equations given 2 points and that are parallel and perpendicular to a given line. And, to write and solve direct variation equations and proportions. 1. Find the slope of the line containing the points (-1,12) and (5,-6). 2. Write the equation in slope-intercept form of the line that has a y-intercept of 0 and a slope of -1. 3. Solve the equations: -3

2. Ex 1 – Write an equation in slope-intercept form for the line in the Warm-up #1. Notes Ex 2 – Write an equation in point-slope form for the line with slope ¾ and contains the point (-12,2) Point-slope form is often used in Calculus!

3. If 2 lines have the same slope, thenthey are parallel If 2 lines are perpendicular, then their slopes are opposite reciprocals Ex 3 – Write an equation for the line a. through (-2,7), that is parallel to

4. b. through (4,-3), that is perpendicular to Direct Variation equation - y varies directly as x as x increases, y increases at a constant rate Other examples?

5. Measure circular objects and complete the table Diameter (x)Circumference (y)Circ/Diam (y/x)

6. Ex 4 – Find the variation constant if y=15 and x=3 Ex 5 – Rita rides her bike 4 miles in 20 minutes. How long will it take to ride 9 miles? Need to find rate

7. Or…Set up a proportion Ex 6 – solve the proportion

8. HW – p. 26 #10,11,22,29,35,38,43,48,78 p. 33 #10,14,17,30,32,37,46,64 Out – when are linear equations not direct variations? How are the graphs different? Summary – I understand… OR I’m confused about… Challenge Probs. For EC…