# 1718 WH3X CH4 Lesson 1

CH4 Types of Relations
Linear Relation (& Directly Proportional)
Fractional Formulas (& Inversely Proportional Relations)
Power Formulas                         Square root Formulas
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Slide 1: Tekstslide
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In deze les zitten 24 slides, met interactieve quizzen en tekstslides. Lesduur is: 50 min

## Onderdelen in deze les

CH4 Types of Relations
Linear Relation (& Directly Proportional)
Fractional Formulas (& Inversely Proportional Relations)
Power Formulas                         Square root Formulas

#### Slide 1 -Tekstslide

Refresh
Solving linear equations
Linear formulas
Exponential formulas

#### Slide 2 -Tekstslide

Solving linear equations
You can solve linear equations with the balance method or sometimes with the cards method.
The balance method means you can add/subtract the same thing on both sides of the = sign and that you can multiply/divide by the same number on both sides of the = sign.
Sometimes you have to remove brackets first.
The cards method lets you place a "card" on the part containing the variable, then you work out what the value of the "card" is.

#### Slide 3 -Tekstslide

Example cards method
5t + 7 = 10

5t = 3

t=0.6

• place a card on "5t"
"3" + 7 = 10
• place a card on "t"
5 x "0.6" = 3

#### Slide 4 -Tekstslide

Solve the equation
3a + 8 = 20

#### Slide 5 -Open vraag

example balance method
3(2a - 4) = 2a - 2

6a - 12 = 2a - 2

4a - 12 = -2

4a = 10

a = 2.5

• remove brackets

• subtract 2a on both sides

• add 12 on both sides

• divide by 4 on both sides

#### Slide 6 -Tekstslide

Solve the equation
5a + 2 = 3a - 8

#### Slide 7 -Open vraag

Linear formulas
General form:
(a is called the gradient and b is called the y-intercept)

Graph: straight line (increasing or decreasing)

#### Slide 8 -Tekstslide

Is this a linear formula?
y = 5 - 2x
A
yes
B
no

#### Slide 9 -Quizvraag

Is this a linear formula?
y = 3x
A
yes
B
no

#### Slide 10 -Quizvraag

Making a linear formula for a line
through two given points
1) Write down the general form of a linear formula: y = ax + b
2) Calculate the gradient using the formula:

3) Fill in the gradient (a) in the general formula
4) Fill in the x and y coordinate of one of the two points in the general formula and calculate the y-intercept (b).
5) Write down the linear formula

#### Slide 11 -Tekstslide

Example
A line passes through point A(3, 5) and B(7, -11).
Give a formula for this line.

1) Write down the general form of a linear formula

#### Slide 12 -Tekstslide

What is the general form of a linear formula?

#### Slide 13 -Open vraag

Example
A line passes through point A(3, 5) and B(7, -11).
Give a formula for this line.

2) Calculate the gradient using the formula:

#### Slide 14 -Tekstslide

What is the correct calculation for the gradient of the line through A(3,5) and B(7,-11)?
A
51137=164=0.25
B
11573=164=0.25
C
37511=416=4
D
73115==4164

#### Slide 15 -Quizvraag

Example
A line passes through point A(3, 5) and B(7, -11).
Give a formula for this line.

3) Fill in the gradient (a) in the general formula

#### Slide 16 -Tekstslide

Example
A line passes through point A(3, 5) and B(7, -11).
Give a formula for this line.

4) Fill in the x and y coordinate of one of the two points in the general formula and calculate the y-intercept (b).

#### Slide 17 -Tekstslide

Solve the equation
5 = -4 x 3 + b

#### Slide 18 -Open vraag

Example
A line passes through point A(3, 5) and B(7, -11).
Give a formula for this line.

5) Write down the linear formula

#### Slide 19 -Tekstslide

Exponential formulas
General form:
(g is called the growth factor and b the initial amount)

Table:                                                here b = 40 (value of h at t = 0)                                                              and g = 0.5  (value you multiply h
with when increase by 1)

#### Slide 20 -Tekstslide

Exponential formulas
example:
What are the initial amount and growth factor for this table?
What is the corresponding formula?

#### Slide 21 -Tekstslide

What formula corresponds to the table?
A
n=6t+2
B
n=2+6t
C
n=26t
D
n=26t

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