How do I use the graph of a linear function to find its equation?
1 Answer
If you have two points on the graph, you can calculate the equation.
Select any two point on the graph. It may make life easier to have two points that are on gridlines in your graph. If one of the points is the
(the
You want to find the equation
where
To calculate the slope
Let's call the two points you selected
Then the slope is how fast
Or in formula (in formulae,
To calculate the intercept
If one of the points you selected is on the
Otherwise you fill in the equation
(substituting the
One example
Step 1: finding
Your points are
Step 2 : finding
Substitute
The complete equation will be:
Step 3: check! your answer:
Fill in the