# 1819 G2X §5.2

Which exercises/theories should we discuss on the board?
1 / 12
Slide 1: Woordweb
WiskundeMiddelbare schoolhavo, vwoLeerjaar 2

In deze les zitten 12 slides, met interactieve quiz en tekstslides. Lesduur is: 50 min

## Onderdelen in deze les

Which exercises/theories should we discuss on the board?

#### Slide 1 -Woordweb

Removing single brackets
In §5.1 you learned how to write a formula such as y = 2t(3t + 4) without brackets, by thinking of the formula as the area of a rectangle with a side of 2t and a side of 3t + 4.
You could also work this out with a multiplication table or by drawing arcs.
Rectangle                             Multiplication table             Arcs

#### Slide 2 -Tekstslide

Removing double brackets
In the same way, you can write formulas such as y = (2t + 3)(3t + 4) without brackets. Think of a rectangle with a side of 2t + 3 and a side of 3t + 4.

#### Slide 3 -Tekstslide

Removing double brackets
What should be written in the
blue rectangle?

I don't know
5t
6t
5t2
6t2

#### Slide 4 -Tekstslide

Removing double brackets
What should be written in the
green rectangle?

I don't know
6t
9t
6t2
9t2

#### Slide 5 -Tekstslide

Removing double brackets
The area is

So
can be written without brackets as

#### Slide 6 -Tekstslide

Removing double brackets

When removing brackets from formulas with negative numbers, you can use a multiplication table. Example: y = (2n - 7)(n + 1)
Put the 2n and -7 in the left column and n and 1 in the top row.

#### Slide 7 -Tekstslide

Removing double brackets

When removing brackets from formulas with negative numbers, you can use a multiplication table. Example: y = (2n - 7)(n + 1)
Put the 2n and -7 in the left column and n and 1 in the top row.
Fill in the table.

#### Slide 8 -Tekstslide

Removing double brackets

When removing brackets from formulas with negative numbers, you can use a multiplication table. Example: y = (2n - 7)(n + 1)
Put the 2n and -7 in the left column and n and 1 in the top row.
Fill in the table.      Write the formula as short                                                                                 as possible.

#### Slide 9 -Tekstslide

Removing double brackets
You can also draw arcs to show what multiplications you are doing. This is sometimes called the "parrot beak" method (do you see the shape?). It is also sometimes called the F.O.I.L. method (firsts, outsides, insides, lasts).
Example:

#### Slide 10 -Tekstslide

Which method should I use?
When being asked to write a formula without brackets, you can choose which method you use (rectangle, multiplication table, arcs, or something else).
You do not have to show how you removed the brackets, but a rectangle/table or steps will show you know how to remove brackets, even if you make small mistakes.

#### Slide 11 -Tekstslide

HW Friday
Make and correct §5.2 (book or digital)