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Quadratic equation graphs

Quadratic equation graphs

From the course: Test Prep: GRE

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Quadratic equation graphs

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- [Voiceover] In addition to graphs of lines, sometimes you're going to have to deal with a graph of a quadratic equation and a lot of times, these guys form parabolas. So I'll give you an example. What if y was equal to x squared minus 4x. Well if we have something in this format, we can still graph it. It's just going to make a different shape. So we can still take advantage of just looking and seeing what the y intercept is. Sometimes there's a number here, like it could be that and we could have like a minus two or something, but since we don't have anything there, we know the y intercept is just zero. So we know one point on that parabola is there. Now, to find some other points we can just start plugging in stuff and see what happens. Like, let's say we plug in negative one for x. So I would say, okay y=-1 squared - 4 times -1. That's a negative one. That's going to turn into y=1- (-4). That's going to simplify to y=5. So x is negative one, y is one, two, three, four, five. All…

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