1. Warm Up 1. Find the shortest distance between point A and segment XZ
2. Are any of these lines parallel? If so, which ones?

2. Slope & Equations in Slope-Intercept Form
Chp 3.5

3. Review of Slope
Slope – a number that describes the direction and steepness of a line
Positive slope:
Uphill – gaining
altitude
Negative slope:
Downhill – losing
altitude
Direction shown by a positive or negative in front of the number:
Steepness shown by the size of the number:
Think of the number as the level of difficulty riding a bike up that hill!
Slope is 5
Slope is 1/4

4. Review of Slope – Special Cases
Vertical Line - undefined slope
(it’s undefined how hard it would be to ride up that hill)
Horizontal Line - zero slope
(it would be zero difficulty to ride up that “hill”)

5. Finding Slope Rise = y₂ – y₁ = 3 – 1 = 2 Run = x₂ – x₁ = 1 – (-2) = 3
Slope (m) = 2/3

6. In Slope-Intercept Form
Equations of Lines
In Slope-Intercept Form
Every line has a LINEAR EQUATION
Slope-Intercept form means the “y” is by itself, and..
y = 3x - 6
Number in front of “x” is the slope (m)
Number at the end is where the line crosses the “y” axis (b)

7. Example Find the slope of this line: Rise = y₂ – y₁ = -2 – 1 = -3
Run = x₂ – x₁
= 5 – 1
= 4
Slope (m) = -3/4

8. Example
Write the equation of this line in slope-intercept form:
Find slope:
Rise = y₂ – y₁
Run x₂ – x₁
Slope-Intercept form: y = mx + b
slope
Y intercept
(2 −0) (0 − −5 ) = 2 5
Find y-intercept: crosses y-axis at +2
(0, 2)
Place numbers in equation: y = mx + b
(-5, 0))
y = 𝟐 𝟓 x + 2