1 / 20

Section 3.5

Section 3.5. Slope-Intercept Form. Page 205. Slope-Intercept Form. The line with slope m and y- intercept b is given by y = mx + b, the slope–intercept form of a line. Example. Page 205. For the graph write the slope-intercept form of the line. Solution

paniz
Télécharger la présentation

Section 3.5

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Section 3.5 • Slope-Intercept Form

  2. Page 205 Slope-Intercept Form • The line with slope m and y-intercept b is given by • y = mx + b, • the slope–intercept form of a line.

  3. Example Page 205 • For the graph write the slope-intercept form of the line. • Solution • The graph intersects the y-axis at 0, so the y-intercept is 0. • The graph falls 3 units for each 1 unit increase in x, the slope is –3. • The slope intercept-form of the line is y = –3x .

  4. Example Page 206 • Sketch a line with slope 3/4 and y-intercept −2. Write its slope-intercept form. • Solution • The y-intercept is (0, −2). Slope ¾ indicates that the graph rises 3 units for each 4 units run in x. The line passes through the point (4, 1).

  5. Slope-Intercept Form Page 206 Find the slope and y-intercept of the line a. y = 5x – 3 m= 5 y- intercept is (0, -3) c. 7x + y = 6 y = -7x + 6

  6. Example Page 206 • Write the y = 4 – 3x equation in slope-intercept form and then graph it. • Solution • Plot the point (0, 4). • The line falls 3 units for each 1 unit increase in x.

  7. Example #46 Page 212 • Write the y = 1/2x-1 equation in slope-intercept form and then graph it. • Solution • Plot the point (0, -1). • The line rises 1 units for each 2 unit increase in x.

  8. Example #54 Page 212 • Write the -2x-y = -2 equation in slope-intercept form and then graph it. • Solution • Plot the point (0, 2). • The line falls 2 units for each 1 unit increase in x.

  9. Example 5 Page 207-8similar to #73 Homeworktry #74 • Modeling cell phone costs: Roaming with a cell phone costs $5 for the initial connection and $0.50 per minute. • Solution • a. If someone talks for 23 minutes while roaming what is the charge? • b. Write the slope-intercept form that gives the cost of talking for x minutes. • c. If the charge is $8.50, how long did the person talk?

  10. Example 5, cont. Page 207-8similar to #73 Homeworktry #74 • Modeling cell phone costs: Roaming with a cell phone costs $5 for the initial connection and $0.50 per minute. • Solution • c. If the charge is $8.50, how long did the person talk? Person can talk 7 minutes.

  11. Example #74 Page 207-8similar to #73 Homework • Electrical Rates: Electrical service costs $8 per month plus $0.10 per kilowatt-hour of electricity used. • Solution • If the resident of an apartment uses 650 kilowatt-hours in 1 month, what is the charge? • Write an equation in slope-intercept form that gives the cost C. • If the monthly electrical bill for the apartment’s resident is $43, how many kilowatt-watt hours were used?

  12. Example #74, cont. Page 207-8similar to #73 Homeworktry #74 • Modeling cell phone costs: Roaming with a cell phone costs $5 for the initial connection and $0.50 per minute. • Solution • c. If the monthly electrical bill for the apartment’s resident is $43, how many kilowatt-watt hours were used? 350 kilowatt-hours used.

  13. Page 208-10 Parallel and Perpendicular Lines

  14. Example Page 208-10 • Find the slope-intercept form of a line parallel to y = 3x + 1 and passing through the point (2, 1). Sketch a graph of each line. • Solution • The line has a slope of 3 any parallel line also has slope 3. • Slope-intercept form: y = 3x + b. The value of b can be found by substituting the point (2, 1) into the equation.

  15. Parallel Lines Page 208-10 Show that the line passing through (4,2) and (6,6) is parallel to the line passing through (0,-2) and (1,0). Slopes are equal

  16. Example Page 208-10 • Find the slope-intercept form of a line passing through the origin that is perpendicular to each line. • a. y = 4x b. • Solution • a. The y-intercept is 0. • Perpendicular line has a slope of • b. The y-intercept is 0. • Perpendicular line has a slope of

  17. Perpendicular Lines Page 208-10 Show that the line passing through (-1,4) and (3,2) is perpendicular to the line passing through (-2,-1) and (2,7).

  18. Example Page 208-10 • Find the slope-intercept form of the line perpendicular to • and passing through the point (1, 0). Sketch each line in the same xy-plane. • Solution • A line perpendicular has slope –3. • The value of b can be found by substituting the point in the slope-intercept form.

  19. DONE

  20. Objectives • Basic Concepts • Finding Slope-Intercept Form • Parallel and Perpendicular Lines

More Related