SOLUTION: write an equation in standard form of the parabola that has the same shape as the graph of {{{f(x)=-7x^2}}}, but which has a maximum of {{{9}}} at {{{x=3}}}.

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: write an equation in standard form of the parabola that has the same shape as the graph of {{{f(x)=-7x^2}}}, but which has a maximum of {{{9}}} at {{{x=3}}}.      Log On


   



Question 237370: write an equation in standard form of the parabola that has the same shape as the graph of f%28x%29=-7x%5E2, but which has a maximum of 9 at x=3.
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!

First let's draw the graph of the first equation:



Notice that since its vertex is %22%280%2C0%29%22 it has a maximum
of 0 at x=0.  Now let's plot the point %22%283%2C9%29%22.



We now need to shift the graph of f%28x%29=-7x%5E2 so that its
vertex %22%280%2C0%29%22 shifts to the point  and the second shifted function h%28x%29.

We first shift the graph horizontally 3 units to the right.
This is done by replacing x in the right side of f%28x%29 by 
%28x-3%29, getting g%28x%29=-7%28x-3%29%5E2. 



But now that graph must be shifted vertically upward by 9 units.
This is done by adding 9 to the right side of g%28x%29,
getting h%28x%29=-7%28x-3%29%5E2%2B9.  Now we draw that graph, and get



So the answer is h%28x%29=-7%28x-3%29%5E2%2B9}.  Notice that it has the
same shape as the original graph of f%28x%29=-7x%5E2.

Edwin