2Tvwo §11.4 AxB=0

• Wiskunde
• Middelbare school
• vwo
• Leerjaar 2

§11.4 A x B = 0

All the 'factorising', done in paragraphs 1, 2 and 3,

will be used today for a special purpose.

So you see that a chapter is not a bunch of loose items!

Recap on §11.2 and §11.3

To work your way much easier through §11.3,

first we look back shortly.

Task 1:

+ Open your Notebook and Textbook on p.178/179:     §11.4 A x B = 0

+ Watch the equations from exercise 28

+ Compare them to those of exercise 35, p.183!

+ What's the main difference between them?

+ Key in your answer shortly in the next slide.

Main difference between equations from 28 and 35 is:
.............................

Solution task 1:

+ The equations from 28 all end with:  ................. = 0

+ The equations from 35 don't end with .............. = 0.

This means that the equations from §11.4, today's paragraph, are easier to solve. Just watch the next slides!

Solving an Equation that is a Product:

A x B = 0.  This equation can only be 0, when

A = 0  or  B = 0     

In the next example the 'A' and the 'B' are expressions with 'x'.

Just watch!

Task 2:

Work out in your head the two Solutions:

The two values for m.  Key in your answers in the next slide

My answer is:
A. 0 and -7 B. 2 and -7
C. 0 and 2 D. -2 and 7

1. 0 and -7
2. 2 and -7
3. 0 and 2
4. -2 and 7

(Task and) Solution:

Homework -part 1

Work on exercises: 

28 and further (so you may skip 26 and 27)

later this LessonUp will be continued!

Now a connection will be made between:

1st:       solving quadratic equations, and

2nd:     graphs for quadratic formulas, so parabolas!

By doing 30 together, you will learn to do the 2nd half of the paragraph.

TASK 3:

+ Think about it for a while.

Solution TASK 3: 

TASK 4:

a. Think about this for yourself.

b. Compare your answer with your neigbors.

TASK 4:

Solution:

In the next slide, this equation will be solved.

TASK 5:

1. Copy the equation in your Notebook and

2. Factorise it.

If you forgot how to Factorise a Trinomial,

look it up on p.175: Method!

TASK 5:

SOLUTION:

TASK 6:        

Make this task in your Notebook.

To refresh your memory:

at 30a we saw that the graph intersects the x-axis at x = -1 and x = 2.

Do you now get the same outcomes?!

TASK 6:        

SOLUTION on the right: 

(Do you remember that we found

the same outcome with the graph?)

Next comes

a bit of Theory,

summarising all this!  

TASK 6:            

This is a FOTOVRAAG !

+ Make 31 a in your Notebook

+ Make a picture of your work

+ Send it in, in the next slide and

+ We get a collection of your Solutions!

31a:

For which values of x does the graph intersect the x-axis?

y=x​2​​+3x−18

Solution TASK 6:

x​2​​+3x−18=0

(x+6)(x−3)=0

X+6=0

x−3=0

x=−6

x=3

x+6=0

Homework-part 2

Make:      §11.4    A x B = 0

Do exercises:

28 t/m 33      You may skip 26 and 27 and also 32.

1. Make it                2. Correct it with the Solutionsbook

3. Send in your results in GC.