# 1819 H2Y §5.Refresh

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

This lesson contains 12 slides, with interactive quiz and text slides.

Lesson duration is: 50 min

## Items in this lesson

What are these graphs called?

#### Slide 1 -Mind map

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 -Slide

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.

#### Slide 4 -Slide

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

#### Slide 5 -Slide

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

#### Slide 7 -Slide

If a formula contains a 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 10 -Slide

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