# 2Tvwo §9.4 Solving inequalities (2)

§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 24 slides, with 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

A balance or a graph...

#### Slide 3 -Slide

Next slide ....
Shows the MEANING of the process of solving an equation.
You get a good idea for what situations it could be used.
Only after that we will watch every little step!

#### Slide 4 -Slide

As you can see in the graphs,
for 30 minutes the water level is the same in A and B.

Task 'e' asks us for which VALUES (so more than one!) of t graph A is HIGHER then graph B

#### Slide 6 -Slide

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

#### Slide 7 -Slide

SOLVING INEQUALITIES:
We don't have graphs (yet), 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 8 -Slide

The following slide shows you an example of this METHOD!

#### Slide 15 -Slide

Practicing solving inequalities!
Now you get a complete example from me to watch and try to understand.
After all this it will be much easier for you to do §9.4 Solving inequalities!

Let's do c now.

#### Slide 18 -Slide

step 1: make an equation:

#### Slide 19 -Slide

step 2: solve this equation:

#### Slide 20 -Slide

step 3: sketch the 2 graphs:
Extra (not really needed):

#### Slide 21 -Slide

step 4: Read off the solution from the inequality:

Solution:

#### Slide 22 -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 23 -Slide

Homework time
DO:
§9.4:      29, 30 and 31
CHECK your WORK with the SOLUTIONS BOOK and
SEND in a few PICS in GC