# Recognise and plot lines y = kx and y = −kx

## Home learning focus

In this lesson you will explore straight line graphs that pass through the origin.

This lesson includes:

• one slideshow
• two interactive activities

Created in partnership with Pearson

# Learn

Work through these slides. You will need to draw some graphs and tables. Using squared paper will make it easier - there may be some in your school Maths workbook.

Lesson summary:

• Graphs of the form y = kx or y = -kx are plotted as straight lines that pass through the origin (0, 0). k represents any number.
• The greater the value of k, the steeper the graph.
• Graphs of y = kx slope upwards. They have a positive gradient.
• Graphs of y = -kx slope downwards. They have a negative gradient.

# Practise

## Activity 1

Recognise and plot lines y = kx and y = −kx

Have a go at the worksheet below from Pearson. Print it out or write your answers on paper.

## Activity 2

Changes to a line

Try this activity from GeoGebra

Move the slider to change the gradient of the line in increments of 0.5, between -5 and +5 and note what changes and what stays the same.

# There's more to learn

Have a look at these other resources around the BBC and the web.