Select the x-coordinate

Question

Select the x-coordinate of the vertex of the parabola defined by the function f(x) = -9x2 + 5x + 6.

Answer 1

f(x) = -9x² + 5x + 6

 

The x-coordinate of the vertex is always located at x = -b/2a for a general quadratic ax²+bx+c. In your case, a = -9 and b = 5:

 

x = -b/2a = -5/(2*(-9)) = 5/18