A2. Linear Relationships Flashcards
Model, analyse and solve problems involving linear relationships
Linear Functions
The equation y = mx + c represents a linear function.
- m =
- c =

The graph of a linear function is a straight line.
- m = the gradient of the line.
- c = y-intercept

Positive and Negative Gradient
Gradient can be positive or negative.

Gradient Formula
The gradient m measures how steep a straight line is.


Finding the Gradient
If you have two points that the line passes through …


Intercepts of a Linear Graph
The intercepts are the points where the line crosses the x and y axes.


Graphing a Linear Function
A linear function can be graphed using its y-intercept and gradient.

[1] Plot the y-intercept on the y-axis.
[2]Use the rise and the run of the gradient to plot the next points on the graph.

Tables of Values & Linear Rules
The rule for a linear relationship can be found from its Table of Values.


Linear Rule from a Table of Values 2
The x-values of some tables of values are not equally spaced.


Linear Rule from Two Points
A variety of questions require you to find the equation of a linear graph given just two points.


Linear Models
A linear model is a mathematical formula that represents the relationship between two variables.

A linear model of Depreciation

Linear Models and Variables
Every linear model has a dependent and an independent variable.

Linear Models and Gradient
To determine what the gradient of a linear model represents, include the units of the two variables when working out the rise over run.


Linear Models and the Vertical Intercept
The vertical intercept (y-intercept) represents the starting value of the dependant variable.

The PC was worth $2000 when purchased.

Direct Linear Variation
In direct linear variation, two quantities, such as time & wages, increase at a constant rate.

For each increase in time of 1 hour, wages increase by $25.

The Direct Linear Variation Equation
The equation that describes direct linear variation is y = kx

y = kx graphs are linear graphs which start at the origin
Constant of Variation
k is called the constant of variation (or constant of proprotionality)

You will usually have to find the value of k at the start of a question (even if the question does not ask you to).

Conversion Graphs
A conversion graph is used to convert between different units (eg metric and imperial units) or between different currencies.

Conversion graphs are another example of the equation y = mx.
Linear Variation Problems

