Ch3L1L2 Equations in Two Variables

Question 1

what is Linear Relationships

Answer 1

Relationships that have straight-line graphs are called Linear Relationships, It must have a CONSTANT RATE of CHANGE

Question 2

How to calculate the Rate of Change?

Answer 2

By using data table as:

Question 3

what is Proportional Linear Relationships

Answer 3

1: ratio between them keep constant

Two variables have a proportional linear relationship when they meet two requirements:

Question 4

What is a Slope ?

Answer 4

Slope if a Rate of Change. Slope can be positvie ( means slanting upward) or negative(slanting downward).

Question 5

How to calculate Slope?

Answer 5

Three ways to get Slope; 1. Slope = rise/run 2.slope = change in y/change in x in a table 3.slope =(y2-y1)/(x2-x1), here (x1,y1),(x2,y2) are any two points on the line.

Question 6

what is Direct Variation

Answer 6

A linear relationship is a direct variation when the ratio of y to x is a constant m.

We also say y varies directly with x.

Question 7

formula of Direct Variation

Answer 7

y = mx

here m also stand for the slope of this linear relationship

Question 8

example of Direct Variation y = mx

in traveling

Answer 8

When we drive at a constant speed, then the distance we drive and time we spend is an example of Direct Variation.

DIstance = Speed x Time

Speed here is the constant m or slope

Question 9

example of Direct Variation y = mx

in working place

Answer 9

When I got a constant weekly salary(salary per week), then the total money I earn and weeks I work is an example of Direct Variation.

Earning = Salary x Time

Here Salary($/week) is the constant m or slope.

Question 10

example of Direct Variation y=mx

when Shopping

Answer 10

At the supermarket, the price of apple is $5/kg, so the money we need to pay and the amount of apple we buy in an example of Direct Variation.

Cost(money to pay) = Price x Amount

Here price(cost per unit) is the constant m or slope.