When given a quadratic equation, how do i graph it, and find the vertex?

So let’s say the equation is x^2 (x squared) -4x + 8 = 0. So you have to eventually graph a palabara. So to get the vertex, you have to find the line of symmetry (this plays a big part). So the formula for the line of symmetry is x= -b/2a. So A is this equation is 1. B is -4. C is 8. So you would plug these numbers in and you get 2. So (2,0) is your like of symmetry. Now you have to plug 2 back in for x. So when you do that you get 4 so the vertex is (2,4). So the vertex is (2, 4) and basically what the vertex is is it is the highest or lowest point of a palabara. So you can tel if it opens up or down by looking is A is negative or positive. If A is negative the it opens down. If it is positive then it opens up. So now you just put points in. Create a t chart. Like x/y. So when X is 1 for example, y is 5. So you graph (1, 5) and you graph the point that is the same distance from the line of symmetry. You do this until you have 5 points. I hope this helps. It’s hard to teach this over text.