3Tvwo § 7.1

§ 7.1 The form f(x)=a(x - s)(x - t)
Let's look at a few fine points of this paragraph!
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This lesson contains 14 slides, with interactive quizzes and text slides.

Items in this lesson

§ 7.1 The form f(x)=a(x - s)(x - t)
Let's look at a few fine points of this paragraph!

Slide 1 - Slide

Question 1     f(x)=(x + 2)(x - 4)
 Explain to yourself why the graph of f intersects the x -axis at points          (-2, 0) and (4, 0)
LET'S ALL THINK ABOUT THIS!
IN SHORT TIME YOU WILL GET AN EXPLANATION!

Slide 2 - Slide

Study this example:

Slide 3 - Slide

NOTE that:

- depending on the information you have, there are 2 ways to       find the points of intersection (= p.o.i.) with the x-axis:
+   1st       If you only have a graph, then you do:   ..........
+    2nd    If you only have this formula: f(x) = 6(x - 5)(x - 3), then               you                           do: ..............

Slide 4 - Slide

answer to the 1st question
(you only have a graph):

Slide 5 - Mind map

answer 2nd question:
(you have this:
f(x) = 6(x - 5)(x -3)

Slide 6 - Mind map

Slide 7 - Mind map

Explanation:
f(x) = 6( x - 5)(x - 3)
To find the p.o.i. with the x-axis, you do this:
x - 5 = 0   or   x - 3 = 0
x = 5   or   x = 3,  so p.o.i. are   (5, 0)  and  (3, 0)

Slide 8 - Slide

Question:
How to find the vertex?
1st: If you only have the graph, you simply read it off.

Slide 9 - Slide

Question:
How to find the vertex?


2nd: If you only have the formula, then you .................... ?!
Try to work this out in the next slide!

Slide 10 - Slide

How to find the vertex for:
f(x) = -1/4(x + 1) (x - 3) ?

Slide 11 - Open question

Statement
x vertex = x for axis of symmetry 
Look at the parabolas in § 7.1 and check if this is true!

Slide 12 - Slide

x vertex = x axis of symmetry
A
not true
B
sometimes true
C
true
D
sometimes not true

Slide 13 - Quiz

Now do the Homework:
§ 7.1
You may skip:
1,  2c, 4cd, 7ab
timer
20:00

Slide 14 - Slide