#### Answer

$-\frac{b}{2a}$

#### Work Step by Step

The vertex of a parabola is located on the line of symmetry. The equation of the line of symmetry is $x=-\frac{b}{2a}$. Therefore the x-value of the vertex must also be located at $-\frac{b}{2a}$.

Published by
Pearson

ISBN 10:
0321785045

ISBN 13:
978-0-32178-504-6

$-\frac{b}{2a}$

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