1718 WB1Z CH12 Lesson 6

• Wiskunde
• Middelbare school
• vwo
• Leerjaar 1

Which exercises/theory should we discuss?

What is the opposite number of -7?

Recap: Opposite numbers

Opposite numbers are numbers that are the same distance away from zero, but on the other side of zero.

-3 and 3 are opposite numbers                  -0.8 and 0.8 are opposite numbers

What is the square of 4?

Recap: Squaring

When you square a number, you multiply the number with itself.

Squaring and negative numbers

If you calculate the square of 3, you calculate 3 x 3 = 9
Notation:

If you calculate the square of -3, you calculate -3 x -3 = 9
Notation:                                                Use brackets!

The number                is the opposite of           and is therefore equal to -9
Notation:                                                    No brackets means opposite number!

Calculate:

(−5)​2​​

1. 10
2. -10
3. 25
4. -25

Calculate:

−6​2​​

1. 12
2. -12
3. 36
4. -36

Calculate the square of -8

1. 8
2. 16
3. 64
4. -64

Quadratic formulas

Formulas that contain the square of a variable are called quadratic formulas.

Example:

Plotting a parabola

The graph of a quadratic formula is called a parabola.
If you want to plot a parabola, make a table first!

Plotting a parabola

                                             Use brackets
                                                when filling in
                                              negative numbers!

Plotting a parabola

Homework Monday

Make and correct:
30 - 39