The document discusses the slope-intercept form of equations of lines. It explains that the slope-intercept form can be written as y = mx + b, where m is the slope and b is the y-intercept. The slope represents how fast the line rises or falls, and the y-intercept is where the line crosses the y-axis. Some examples of lines in slope-intercept form are worked out, identifying the slope and y-intercept in each case.

1. Slope-intercept form of equations of lines

2. Graphing a Line
 There are two key y-intercept
concepts you need to
understand about lines:
 Y-Intercept – where the
line touches the y-axis
(the vertical axis)
 Slope – How fast the line
rises or falls

3. Equation of a Line
 The equation of a line can be written as:
y = mx + b
m = slope
b = y-intercept
x and y are the points on the line –
in the equation, they are variables!

4. Identifying Slope and y-intercepts
What are the slope and y-intercept of:
y = 2/3 x – 4
Slope = 2/3 (it is in the m spot!)
y-intercept = -4 (it is in the b spot –
notice, it’s negative because of the
minus sign!

5. You try some!
 What are the slope and y-intercept of:
1) y = -2x + 4 2) y = x – 4
3) y = -1/2 x – 5 4) y + 2 = 3x (be careful on this!)
Check the next slide for the answers!

6. Answers
1) Slope = -2, y-intercept = 4
2) Slope = 1, y-intercept = -4
3) Slope = -1/2, y-intercept = -5
4) Slope = 3, y-intercept = -2 (you have to subtract 2
first!)