To find the equation of a line from its graph

- Find the gradient of the line, m
- Write down the value of the y-intercept, c.
- Substitute into y = mx + c

Example

Write down the equation of the line shown

To find the gradient, use

or the gradient formula

either way, this gives m = -2

Write down c = 2

Write down y = mx + c

so the equation of the line is

y = -2x + 2