Hey, everyone. So in a previous video, we were introduced to the slope intercept form of a line, y=mx+b. And we saw some problems where a graph of a line was already given to us, and we wanted to write the equation in slope intercept form. But in some problems, like the one we're going to work out here, you actually will do the opposite. You'll have the equation that's already given to you, and you'll be asked to graph it. So that's what I'm going to show you how to do in this video, how to graph lines when you're given the equations in slope intercept form. And, basically, what I'm going to show you is that a line equation in this form tells you everything that you need to graph it very quickly. And I'm going to show you a step by step way to do that. So let's just jump right into our example and get started here. So we have the equation y=23x+1, and the first thing we want to do is we want to identify the y-intercept and then the slope over here. So let's get started. Remember, the y-intercept is just the b term in y=mx+b. So if you look at this equation, y=23x+1, what you'll see here is that the b is basically just the 1. It's the thing that's constant at the end, and the m is just the slope. It's the thing that goes in front of the x, which is 23. So right from this equation, we could just immediately pull out the fact that the b term is just 1. That's the y-intercept, and the slope is just a fraction, which is 23. So how do we graph this? Well, the first thing you're going to do is you're just going to plot the y-intercept. That's the easiest thing to plot because you don't have to calculate anything. You're just sort of marking a place on the graph. The y-intercept is the y value where it crosses the y axis, so I know that this graph is going to cross through this point. But that's not enough information to graph this because I don't know if it's going to look like this or this or that, so I'm going to need more points. So that actually brings us to the second step here, which is we're going to plot at least one more additional point, and the way we do that is by using the definition of slope. Remember, slope is just rise over run. So in other words, we have to go rise 2, and then we have to run over by 3 in order to get to the next point. So, basically, you're going to take your y-intercept here, and you're just going to go up 2. You're going to rise 2, and then you have to go over 3. Just do rise over run to get to the next point. You can either go up to the right or you could go down to the left. All you really need is just one additional point. Now once you've done that, now you're basically done because all you have to do is just connect the points with a line. So, again, you could have gone downwards like this, and this basically would have just gone down 2 and over 3. But, anyways, you would actually end up seeing that the equation of your line kind of goes through all three of these points, and it looks something like this. Alright? So that's how we go from an equation to a graph in 3 simple steps. Hopefully, that made sense. Thanks for watching.
- 0. Fundamental Concepts of Algebra3h 29m
- 1. Equations and Inequalities3h 27m
- 2. Graphs1h 43m
- 3. Functions & Graphs2h 17m
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2. Graphs
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