1. 5.2.2 – Intercept Form

2. We have covered two forms of quadratics;
Standard Form; y = ax2 + bx + c
Vertex Form; y = a(x – h)2 + k
The third will also us to find two specific points on the graph, if they exist

3. Intercept Form
Recall, the x-intercepts are the points a graph crosses the x-axis
Intercept Form is expressed as;
y = a(x – p)(x – q), where p and q are the x-intercepts

4. Be careful!
Similar to the vertex form of a parabola, we must think opposite when it comes to finding the intercept values
So, if shown y = a(x – 4)(x + 3), the intercepts are x = 4 and x = -3, not the opposite

5. Example. Determine the x intercepts for the following equations
A) y = 2(x – 3)(x – 5)
B) y = (x + 9)(x – 3)
C) y = -9(x + 4)(x)
D) y = 4(x – 5)2

6. Graphing
Using the intercepts, we will be given two of the three points we need
What is the third point we will need?
Vertex;
x = (p + q)/2,
then plug back in to
get the y-value

7. Example. Graph the following equation
Example. Graph the following equation. Label the vertex and y-intercepts.
y = (x – 3)(x – 7)

8. Example. Graph the following equation
Example. Graph the following equation. Label the vertex and y-intercepts.
y = 2(x + 4)(x – 4)

9. Example. Graph the following equation
Example. Graph the following equation. Label the vertex and y-intercepts.
y = -2(x + 1)(x – 3)

10. Assignment
Pg. 231
13-21, 28-30, even
Due MONDAY
Quiz tomorrow!

13. Working together, find the graphs for the following equations;
1) y = (x – 2)(x + 6)
2) y = -(x – 3)(x – 6)
3) y = 3(x + 3)(x – 1)
We will go over the assignment together afterwards.