Year 8 Interactive Maths - Second Edition

Sketching Linear Graphs

It is convenient to find the points where a graph cuts the axes.  The points where a graph cuts the x-axis and y-axis are called the x-intercept and y-intercept respectively.

It is clear from the graph that:

• The x-intercept occurs when y = 0.
• The y-intercept occurs when x = 0.

Example 9

Draw a sketch for the linear equation y = 2x + 4.

Solution:

y = 2x + 4

x-intercept:

y-intercept:

Example 10

Draw a sketch for the linear equation y = –3x + 6.

Solution:

y = –3x + 6

x-intercept:

y-intercept:

Key Terms

axes, x-intercept, y-intercept, sketch graph