# finding a and b in quadratic function

• May 7th 2014, 03:00 AM
xwy
finding a and b in quadratic function
Hello everyone, I do not how to initiate the first step for this question. However, I know it has to do with the vertex and the axis of symmetry. The attached image is the question. Pls help me out!Attachment 30856
• May 7th 2014, 03:16 AM
Prove It
Re: finding a and b in quadratic function
The axis of symmetry is x = -b/(2a).
• May 7th 2014, 09:48 AM
HallsofIvy
Re: finding a and b in quadratic function
Alternatively, if the axis of symmetry is x= -3/8 the quadratic is of the form \$\displaystyle y= a(x+ 3/8)^2+ e\$. The fact that "c" is equal to 7 will allow you to find one of a and e as a function of the other but you cannot determine both.
• May 7th 2014, 05:03 PM
Prove It
Re: finding a and b in quadratic function
Quote:

Originally Posted by HallsofIvy
Alternatively, if the axis of symmetry is x= -3/8 the quadratic is of the form \$\displaystyle y= a(x+ 3/8)^2+ e\$. The fact that "c" is equal to 7 will allow you to find one of a and e as a function of the other but you cannot determine both.

The question asks for A possible function, not THE possible function.