SOLUTION: How Do I Do This? f(x) = 3x - 9

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Question 577936: How Do I Do This?
f(x) = 3x - 9

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
What do you want to do? Do you want to graph? If so, then f(x) = 3x - 9 is the same as y = 3x - 9


Looking at y=3x-9 we can see that the equation is in slope-intercept form y=mx%2Bb where the slope is m=3 and the y-intercept is b=-9


Since b=-9 this tells us that the y-intercept is .Remember the y-intercept is the point where the graph intersects with the y-axis

So we have one point




Now since the slope is comprised of the "rise" over the "run" this means
slope=rise%2Frun

Also, because the slope is 3, this means:

rise%2Frun=3%2F1


which shows us that the rise is 3 and the run is 1. This means that to go from point to point, we can go up 3 and over 1



So starting at , go up 3 units


and to the right 1 unit to get to the next point



Now draw a line through these points to graph y=3x-9

So this is the graph of y=3x-9 through the points and