1 / 9

Lines

Lines. Slope and y-intercept. Lines. Lines have both slope (m) and a y-intercept (b). Slope describes the steepness of the line as well as its direction. Positive slope means the lines go up toward the right; negative slope means it goes down to the right.

pier
Download Presentation

Lines

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. Lines Slope and y-intercept

  2. Lines • Lines have both slope (m) and a y-intercept (b). • Slope describes the steepness of the line as well as its direction. • Positive slope means the lines go up toward the right; negative slope means it goes down to the right. • The larger the slope, the steeper the line. • A slope of 5 is a very steep line, while a slope of 1/5 is very flat. • The y-intercept tells you where the line crosses the y-axis.

  3. Slope • Slope is the rise over the run. • We find slope using the equation: • m = • Slope is always a fraction or a whole number. • Slope is telling you how to move to find other points on the lines. I do not know how to move in decimals. • Find the slope of the line that passes through (5,2) and (4,9). • m = • m = • m = - 7

  4. Slope • You only get better when you practice, so….. • Find the slope of the line that passes through the points: • 1. (4,4) and (6,6) 2. (3,7) and (4,8) • m = 1 m = 1 • 3. (7,-5) and (-4,-4) 4. (-6,-1) and (7,-6) • m = -1/11 m = -5/13

  5. Slope - Intercept • Slope tells you how to move and the y-intercept tells you where the line cross the y-axis. • y = mx + b……you have seen this before • m is the slope and b is the y-intercept. • When giving the y-intercept, give the coordinates as an ordered pair. (0,b) • You can use those two things to graph any line. • y = 2x + 3 • Slope is 2 and the y-intercept is (0,3).

  6. Slope-Intercept • Try a couple more……. • 1. y = 5x – 6 2. y = -2x + 3 • 3. y = -1/3x + 6 4. y = 1/2x - 4

  7. Slope-Intercept • Now we will practice writing equations. • Remember you have to have a slope (m) and a y-intercept (b) to write an equation. • Write the equation for the line given the slope and intercept. • 1. m = 2 y-intercept (0,5) • 2. m = -8 y-intercept (0,4) • 3. m = ½ y-intercept (0,-3) y = 2x + 5 y = -8x + 4 y = 1/2x - 3

  8. Slope-Intercept • Now for the hard ones…… • What happens if you have the slope, but not the y-intercept? • Solve for it!!! • Write the equation of the line that has a slope of 2 and passes through (4,6). • y = mx + b • 6 = 2(4) + b • 6 = 8 + b • b = -2 • y = 2x - 2 Plug in the numbers that you know: m = 2, y = 6, x = 4 Solve for b. Rewrite in slope-intercept form.

  9. Slope-Intercept • I know, that was tricky so try it again…. • m = 4 (-1,2) • 2 = 4(-1) + b • 2 = -4 + b • b = 6 • y = 4x + 6 m = -1/2 (4,-6) -6 = -1/2(4) + b -6 = -2 + b b = -4 y = -1/2x - 4

More Related