# 2TTO §9.4 Solving inequalities (1) PTI

§9.4 Solving inequalities
(ongelijkheden)
Up to now we only dealt with equations, so:
'something being equal to something else'.
However,
something could also be greater than or smaller than                                      something else!
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Slide 1: Slide
WiskundeMiddelbare schoolvwoLeerjaar 2

This lesson contains 36 slides, with interactive quizzes and text slides.

Lesson duration is: 50 min

## Items in this lesson

§9.4 Solving inequalities
(ongelijkheden)
Up to now we only dealt with equations, so:
'something being equal to something else'.
However,
something could also be greater than or smaller than                                      something else!

#### Slide 1 -Slide

Below you see what you will learn and the kind of tasks
you are going to solve. But how?!

Do you remember the signs:
for 'smaller than'       and
for 'greater than'?

#### Slide 2 -Slide

In this lesson .....
+ we will march through the first part of §9.4 together
(no need to do them later, anymore!)
+ homework will be p.102:           26, 27, 29, 30 and 31

Next slide has a lotta text. Read this for yourself first.
Of course you can take your own book 2B, p.100 , where it's from!

#### Slide 3 -Slide

jk
Answer the 1st question only, so:
Is it possible that the bags each contain 4 marbles?

#### Slide 4 -Slide

4 marbles; is that possible?!

#### Slide 5 -Mind map

No!            Why not?       Look below:

Keep in mind that the left side is heavier, so it contains more marbles!

#### Slide 6 -Slide

jk
Answer the 2nd question only, so:
Is it possible that the bags each contain 8 marbles?

#### Slide 7 -Slide

Is 8 marbles possible?!

#### Slide 8 -Mind map

Yes!    Why?    Look below:

Why is this possible? Because the right side is heavier and it contains more marbles!

#### Slide 9 -Slide

A balance or a graph...

For an amazing balance, watch next slide!

#### Slide 11 -Slide

We are going to do 27 now.  It is much handier if you open your own book, p.101, of course!

#### Slide 12 -Slide

And now, bit by bit...

#### Slide 17 -Slide

Graph A is steeper because ...
(tell from the formulas!)

#### Slide 19 -Slide

Answer is shown in the next slide.

#### Slide 21 -Slide

Think about it again for a while.
Answer is shown in next slide.

#### Slide 24 -Slide

You have been doing great up to now!
This LessonUp takes a lot of our time, but remember:
pages 100 and 101 too we have almost finished now!

Finally here comes the METHOD how to
SOLVE an INEQUALITY (ongelijkheid).

#### Slide 25 -Slide

From now on, it's the other way around:
We don't have a graph, but just an INEQUALITY!
In order to SOLVE this,
we will make a SKETCH of the two graphs ourselves.
Next slides show how to do all this!

#### Slide 26 -Slide

The following slide shows you an example of this METHOD!
Then the points 1, 2, 3 and 4 correspond to those above!

#### Slide 30 -Slide

What is the next step to take?

#### Slide 34 -Slide

After all is said and done ...
There are exercises 29, 30 and 31 to be done by yourself.
In 29 and 30 no graphs are given, so just

+ work out the 4 points from the Method on p.102, we just went through
+ making sketches of both graphs, etc.

#### Slide 35 -Slide

Homework time
DO:
§9.4:      29, 30 and 31