A quadratic of the form \(-2x^2 + bx + c\) has roots of x = 3 + sqrt5 and x = 3 - sqrt{5} The graph of y = -2x^2 + bx + c is a parabola. Find the vertex of this parabola.

I think I might know how to start this, but any hints appreciated!

violetzhang07 Oct 6, 2020

#1**+1 **

This equals (x-3-sqrt5)(x-3+sqrt5)

c would equal the red parts multiplied together and then multiplied by -2 ( because the x^2 has a -2 coefficient)

b would equal the red parts added together and multiplied by -2

Vertex 'x' value is then = -b/2a get the y value of the vertex by putting 'x' into the equation and calculating....

Guest Oct 6, 2020