# Question #53a4c

##### 1 Answer

May 17, 2015

The vertex of the parabola

Right away it's important to realize that this is a quadratic equation of the form

The line of symmetry (or axis that passes through the vertex) of the parabola will always be -b/2a. "B" in this case is 8, and "a" is -4, so

This means the x value of the vertex will be 1. Now, all you have to do to find the y-coordinate is plug '1' in for x and solve for y:

So the vertex is (1, -3), as seen in the graph below (roll over the vertex to see the coordinates). graph{-4x^2 + 8x - 7 [-8.46, 11.54, -9.27, 1.15]}