We have seen graphs in the form y = mx + c before.

When a graph is written in the form y = mx + c, **m** represents the gradient and **c** represents the **y** intercept.

Take the example of the cost of a taxi ride at £1 + £3 per mile. In this case the gradient is the cost per mile and the intercept the £1 standing charge.

This can be written as y = 3x + 1

This line has a gradient of 3 and a **y** intercept of 1.

We can use this information to plot the graph, without drawing a table.

The line cuts the y-axis at 1 so the y intercept is 1.

The line has a gradient of 3 because every time it goes along one square it moves up 3 squares (every mile costs £3).

- Question
Plot the graph of y = -x + 2 without using a table

- Answer
m = -1 and c = 2, so the line cuts the y axis at 2 and has a gradient of -1.

The graph should look like this:

**Remember,** if the gradient is negative, the graph will slope up to the left.

**Now try a **Test Bite.

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