# How to plot straight line graphs

## Home learning focus

Learn how to plot straight line graphs.

This lesson includes:

• one video
• learning summary
• one activity sheet

# Learn

For students looking to achieve grade 4 in GCSE Maths, students must know that a linear equation is drawn as a straight line on a set of axes. A table of values can be used to plot straight line graphs.

Check your understanding of how to draw a graph of a linear equation by watching this short video from BBC Bitesize, KS3 Maths.

Read pages 1 to 4 of our 'Straight line graphs' Bitesize revision guide. To understand:

## How to draw a graph of a linear equation

A linear equation can be represented as a line graph. In order to draw the line graph we require several pairs of coordinates. These coordinates represent the relationship given in the equation.

For example, for y = 3x, the y value is always equal to '3 lots' of the x value. (1,3), (10,30) and (2.5,7.5) are all coordinates on the line y = 3x.

Often a table of values is used to create the coordinates. We use substitution to calculate the values.

For example: y = 2x + 1

The y value is always '2 lots' of the x value plus 1.

We replace the value of x for different numbers and record the resulting y value.

## An example of how to plot a straight line graph

Draw the graph of the equation y = 3x - 1.

Create a table of values to find the coordinates on the graph:

Plotting the coordinates and drawing a line through them on a graph looks like this:

This is the graph of y = 3x - 1.

To learn more on how to plot straight line graphs look at the Straight line graphs Bitesize guide here.

# Practise

## Activity 1

Equations on a straight line

Complete the activity sheet from Beyond on equations on a straight line to test your knowledge.