1. Today’s Lesson: Intercepts
(6.3)
What are they?
What do they mean?
How can I find them?
What can I do with them?

2. Hmmm… what do you think ‘intercept’ means?
Can you think of a sport that talks about a ball being intercepted?

3. In football, when someone intercepts a pass it means he/she is crossing the path of the ball (and stealing it from the other team)
This is when the player and the ball meet
On graphs, an intercept is where a line and the axes meet

4. Intercepts: the points where a relation crosses the axes
What are they?
Intercepts: the points where a relation crosses the axes x y
y-intercept
x-intercept
Here’s a visual for you…

5. The starting distance, before any time has passed.
What do they mean?
Distance (m) vs. Time (s) 1 2 3 4 5 6 7 8 9 10 11
Time (s)
Distance (m)
What does the y-intercept mean with respect to this graph?
The starting distance, before any time has passed.

6. The time it took for distance to become 0.
What do they mean?
Distance (m) vs. Time (s) 1 2 3 4 5 6 7 8 9 10 11
Time (s)
Distance (m)
What does the x-intercept mean with respect to this graph?
The time it took for distance to become 0.

7. What do they mean? Write an equation for this relationship.
Distance (m) vs. Time (s) 1 2 3 4 5 6 7 8 9 10 11
Time (s)
Distance (m)
Write an equation for this relationship.
y = - 1x + 5 2

8. The starting height, before any time has passed.
What about this one?
Height of Flower (cm) vs. Time (wks) 2 4 6 8 10 12 14 16 18 20 1 3
Time (wks)
Height (cm)
What does the y-intercept mean with respect to this graph?
The starting height, before any time has passed.

9. What about this one?
Height of Flower (cm) vs. Time (wks) 2 4 6 8 10 12 14 16 18 20 1 3
Time (wks)
Height (cm)
If the line were extended, what would the x-intercept be?
-0.5
x – intercept would be -0.5

10. What about this one?
Height of Flower (cm) vs. Time (wks) 2 4 6 8 10 12 14 16 18 20 1 3
Time (wks)
Height (cm)
Does the x-intercept have any meaning in this relationship?
-0.5
No! It would be how long ago the flower was at a height of zero, which is not realistic.

11. What about this one? Write an equation for this relationship.
Height of Flower (cm) vs. Time (wks) 2 4 6 8 10 12 14 16 18 20 1 3
Time (wks)
Height (cm)
Write an equation for this relationship.
y = 5x + 3

12. How can you use this information to find the intercepts?
How can I find them?
What is the x-value at any point on the y-axis?
What is the y-value at any point on the x-axis? x y
x = 0
y = 0
How can you use this information to find the intercepts?

13. How can I find them? x y
y-intercept
 let x=0
x-intercept  let y=0

14. What can I do with them? You can graph! y Find the interceptsx y
Find the intercepts
Plot them on the Cartesian Plane
Draw a line through the intercepts
Don’t forget the arrows!