# 2ndF/3rdF Factorising and Solving Trinomials

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

In deze les zitten 15 slides, met interactieve quiz, tekstslides en 1 video.

Lesduur is: 50 min

## Onderdelen in deze les

Which exercises/theories shall we discuss on the board?

#### Slide 1 -Woordweb

Recap: Binomials and Trinomials
A formula like                                 is called a binomial
(bi = 2, the formula has 2 terms)

A formula like                                           is called a trinomial
(tri = 3, the formula has 3 terms)
y=3x2+6x
y=x2+7x+10

#### Slide 2 -Tekstslide

Removing double brackets

#### Slide 3 -Tekstslide

Factorising trinomials
What do you notice?

#### Slide 4 -Tekstslide

Factorising trinomials
If a trinomial is of the form
(so 1 in front of x-squared, a number in front of x and a single number)
then you can factorise the formula with double brackets

For the numbers on the dots you should find two numbers so that:
.... + .... = b                  the sum of the two numbers in the number in front of x
.... x .... = c                   the product of the two numbers is the single number
y=x2+bx+c
y=(x+...)(x+...)

#### Slide 5 -Tekstslide

Factorising trinomials
Factorise
Make a multiplication table.

We need two numbers on the dots
... + ... = 8
... x ... = 12
y=x2+8x+12

#### Slide 6 -Tekstslide

Factorising trinomials
Factorise
Make a multiplication table.

We need two numbers on the dots
2 + 6 = 8
2 x 6 = 12
So the factorised formula is
y=x2+8x+12
y=(x+2)(x+6)

#### Slide 7 -Tekstslide

Try it yourself!
Copy and make this exercise in your Notebook!

Factorise
Make a multiplication table.

We need two numbers on the dots
... + ... = ...
... x ... = ...
So the factorised formula is
y=x2+3x18

#### Slide 8 -Tekstslide

SOLUTION:
Compare with your own work and

Factorise
Make a multiplication table.

We need two numbers on the dots
6 + -3 = 3
6 x -3 = 18
So the factorised formula is
y=x2+3x18
y=(x3)(x+6)

#### Slide 9 -Tekstslide

Suppose.....
We have no 1 in front of the x squared!?
For example, How to:
Solve -0.2 x squared + 3x - 10 = 0  ??!

#### Slide 11 -Video

Pokemon ??!
No:
Difficulty in MATH !!

#### Slide 12 -Tekstslide

Once more:
How to solve:
-0.2x squared + 3x - 10 =0 ?
First we multiply all terms on both sides of the = sign by -5!
You get:   x squared -15x + 50 = 0
NOW SOLVE THIS EQUATION IN YOUR NOTEBOOK!

#### Slide 13 -Tekstslide

SOLVE:   x squared -15x + 50 = 0
SOLUTION:
(x - 10)(x - 5) = 0
x - 10 = 0  or  x - 5 = 0
x = 10  or  x = 5

#### Slide 14 -Tekstslide

Homework
Make and correct with your Solutionsbook:
REFRESH Ch 4, p.116/117
Good luck!