Jim B. answered • 04/20/15
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Plot the points, to get a graph similar to
http://hwmath.net/solutions/x26x8.jpg
You can see that it is not a straight line, this will be a quadratic equation.
The way to determine the equation will depend on what methods you have learned or are learning and what tools you are using. Can you tell from the shape of this graph or the y-intercept what the equation is?
You can check your equation with each of the data points that you listed.
One way to proceed, after realizing this is quadratic and in the form x2 + bx + c
From your table you can start with the value of y, subtract x2, then subtract c, and then you will be able to see a pattern to solve for b (or look in the row where x=1). Then plug in 100 for x.
Jim B.
You are looking for function of x, f(x) so that when you take one of your values of x from the table you will get the corresponding value in the table for y.
When you graph the function, every point on the graph will be a solution to the equation (function).
From the graph you can see that this is not a straight line, so your equation will not be in the form of y=mx + b. But this will fit a quadratic equation that has the form of y = x2 + bx + c and now you need to figure out what the value of b and c are. From the graph and from the table you can see that the y-intercept is 8, so c=8
So if y = x2 + bx + c then solve for bx
y - x2 - c = bx
Update your table to include the following fields to help you determine what the value of b is, so you can finish the equation
x y x2 y-x2 y - x2 - 8 =bx
--- --- --- ----- ----------
0 8 0 8 0
1 15 1 14 6
2 24 4 20 12
3
4
5
So what is b?
What is the equation that matches your table?
Can you find rows in the table that can help you find b and c faster?
When you are looking for help, try to explain what you know and what you need help with, and phrase it in the form of a question such as "I get ______ so I did ______ but why ______?" Ideally when you get any answer to a question it would be in the form of another question so that you can deepen your understanding of both the question and the solution. My best answer would have related back to the methods that you have used in school but of course I can't know what that is so I posted something for you to consider :)
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04/21/15