# 2TH §5.0 Refresh

What are these graphs called?
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Slide 1: Woordweb
WiskundeMiddelbare schoolhavo, vwoLeerjaar 2

In deze les zitten 15 slides, met interactieve quiz en tekstslides.

Lesduur is: 50 min

## Onderdelen in deze les

What are these graphs called?

#### Slide 1 -Woordweb

Quadratic formulas are the type of formulas you will use most often in Mathematics.
Working with quadratic formulas requires you to work precisely and neatly and you need the skills you've learned in previous chapters.

#### Slide 2 -Tekstslide

Recap: Order of Operations
When doing calculations, you have to follow the order of operations:
1. First calculate what is given between brackets.
2. Then calculate powers and roots.
3. Then multiply and divide from left to right.
4. Then add and subtract from left to right.

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#### Slide 5 -Tekstslide

Recap: Square roots
The square root of 25 is 5, because the square of 5 is 25.

The square root of 6.25 is 2.5, because the square of 2.5 is 6.25

There is no square root of -16 (or any other negative number), because, there is no number you can square, to get a negative result

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#### Slide 7 -Tekstslide

Recap: Writing formulas shorter
You can write formulas shorter by:
- multiplying factors
- combining like terms
- not writing down the multiplication sign between a number and a variable

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#### Slide 10 -Tekstslide

If a formula contains  the square of a variable (and not a higher exponent), it is called a quadratic formula.The corresponding graph is called a parabola.

When filling in negative numbers for the variable in a quadratic formula you should use brackets, because you want to square the negative number, not take the opposite of a positive square.

#### Slide 14 -Tekstslide

HW Thursday
Do all the §5.0 Refresh exercises and correct them