Lectures and Quick Notes(1.1)
Chapter
Chapter 1
Section
Lectures and Quick Notes(1.1
Lectures and Notes 10 Videos

Section Intro

Converting Word into Algebra for the basic Operations

example 1: Convert the following into algebra to expressions:

• "+": 4 more than a number
• "-": 4 less than a number
• "\times": Three "times" a number
• "of": Three of a number OR half of a number

See video for details

3.57mins
Converting Word into Algebra for Sum Subtraction and Multiplication

Converting Words into Algebra Equation

A first example with percentage

example: 60\% of the school population is 300. What is the 100\% of the population?

See video for details

Solution:

500 is the population of the school.

1.51mins
Converting Words into Algebra Equation

Converting words into Equations

example: Find a number when subtracted by 4 it's the same as when the number has been increased by 3 and then halved.

See video for steps

n = 11

2.10mins
Converting Words into Equations ex1

Typically here is what we do when we talk about division:

• dividend ÷ divisor = quotient

See Video for Details

Converting Division word programs into Algebra Expressions

Modelling Cost of items

Jim is looking to buy a mixture of two coffee beans in StarCoffee. There are two different types of roast: Pike and Blonde. Jim is going to spend a total of \$24 on coffee beans. The Pike roast cost \$8/kg and the Blonde roast cost \\$6/kg.

(a) Write an equation to represent Jim's purchases.

(b) Isolate the variable for the number of jellybeans in your equation.

(c) If Jim bought 250 g of Pike, how many grams of Blonde did he buy?

(d) If Jim bought 150 g Blonde, how many grams of Pike did he buy?

4.24mins
Modelling Cost of items

Geometry Set Up Example

ex The length of a rectangle is 4 cm less than 3 times the width. The perimeter is 36 cm. Find the width and length.

Therefore, the width of the rectangle is 5.5 cm and the length of the rectangle is 12.5 cm.

2.50mins
Geometry Set Up Example

ex Two consecutive numbers add up to 55. What are the two numbers?

1.47mins
Consecutive Numbers

Graphing Lines

Intersection of Lines

example: Find the intersection point between the two lines below.

• \displaystyle y = \frac{1}{2}x -1
• \displaystyle y = -\frac{3}{4}x + 6

The two lines share the point of intersection say (a, b).

Since (a, b) is on both lines they can be now written in terms of a and b in the following way.

• \displaystyle b = \frac{1}{2}a -1
• \displaystyle b = -\frac{3}{4}a + 6

Therefore,

\displaystyle \left(\frac{28}{5}, \frac{9}{5}\right)