SOLUTION: Can you write the equation of a parabola when given only the coordinates of the vertex

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Question 88156: Can you write the equation of a parabola when given only the coordinates of the vertex
Answer by Edwin McCravy(6940) About Me  (Show Source):
You can put this solution on YOUR website!
Can you write the equation of a parabola when given only the coordinates of the vertex?


No.  The equation of a parabola is 

f(x) = a(x - h)² + k

where (h,k) = the vertex.  However, the smaller the value of |a|,
the wider the parabola and the larger the value of |a|, the narrower.
When "a" is a positive number, the parabola opens upward. When "a" 
is negative the parabola opens downward.   

Here are five different parabolas, all with the same vertex 
(h,k) = (3,-2) but with different values of "a".

graph%28400%2C400%2C-10%2C10%2C-10%2C10%2C%28x-3%29%5E2-2%2C+2%28x-3%29%5E2%2F13-2%2C+-3%28x-3%29%5E2-2+%2C+4%28x-3%29%5E2-2%2C-%28x-3%29%5E2%2F7-2+++%29

Edwin