Sign In
Recall and implement two different forms of the line equation.
See solution.
Suppose that we have the graph shown below.
Using this example graph, we will illustrate two methods to find the equation of a line given its graph.
y-y_1 = m (x-x_1) Here m is the slope of the line and (x_1,y_1) is a known point on the line. The first thing to do is to identify a point. Then, we can move from it while counting the rise and the run to find the slope.
Substitute values
Distribute 1.5
LHS+1=RHS+1
We can also find the line equation using the slope-intercept form. y = mx + b Here m is the slope of the line and b is the y-intercept. Once again, let's start by identifying these features in the graph.
We now proceed to calculate the slope, just as we did above. We will not show that again, and we will just use its value — m=1.5. We can see from the graph that in this case, b=1. If we substitute these values into the slope-intercept form, we will find our line equation. y = 1.5x + 1