Linear Equation Graphs
Linear equation graphs are always a straight line. And you just need two points to draw a straight line (try it out!), which is the key to drawing the graphs.
If you're looking to find the linear equation from a graph, check out our step-by-step guide below. If you're looking to graph a linear equation, scroll down to our linear equation grapher.
Graph to Linear Equation
There are five easy steps to getting the linear equation from a graph:
- Find two points: We need two points to figure out our equation. So, we should look for two points that have whole numbers as and coordinates.
Let's say this is our graph:We're going to pick the two blue points, which are and .
- Get the slope: Next, we need to use our two points to get the slope of the line. Let's remember how to get the slope...So, with our two points, our slope is:
Slope FormulaLet's say we have two points: Point 1 with coordinates and Point 2 with coordinates . The slope is given by the change in by the change in :
- Slope-intercept form: Now, we can plug our slope into slope-intercept form, which is
where is the slope. Plugging in our slope of 3, we get
- y-intercept: Finally, we need to get our value for . We can do this, by plugging in one of original points. We're going to choose the first point: Plugging in, we get this:
If we solve this equation, we get:
- Final equation: Now, we can plug our value in to get our equation:
There are four easy steps to graphing a linear equation:
- Slope-intercept form: We need our equation to be in slope-intercept form,
where and represent numbers. Enter in some numbers for and .