Graphing Slope Intercept Functions on Geogebra
Here is an example of the three equations that I graphed using Slope Intercept Form. The three equations I used were:
i)
ii)
iii)
First I had to transform the equations into their slope intercept form. I'll demonstrate how on the last example since it is trickiest.
We begin with
.
We have to remember that in slope intercept form, y is isolated on one side, so we focus on doing that. First we subtract 2/5 from both sides and we get
.
Next we divide by 1/5, or equivalently, we multiply by its reciprocal, 5/1 on both sides. We then get
.
And now that it is in slope intercept form we can graph it!
Remember that slope intercept form is y=mx+b, where m is our slope and b is our y-intercept.
So in this case, our slope is 5 and our y-intercept is -2.
When plotting in slope intercept form, we plot our y-intercept first. Since our y-intercept is -2, we plot the point (0,-2).
Next we use our slope to find our second point.
Slope is "Rise over Run," or "Rise"/"Run."
Since our slope is 5, then the "Rise"/"Run" is 5/1. So for every 5 units that we rise UP, we run OVER to the right by 1 unit. So our next point from (0,-2) is (1,3). We can now use the Line tool in GeoGebra to graph our function!