Question

PLEASEEEEE
Find the vertex of the parabola formed by the following quadratic function: y = -x2 + 10x - 1
(-10, -201)
(5, 24)
(-5, -76)
(10, -1)

Answer 1

the formula for the x-coordinate of the vertex of a parabola (ax2 + bx + c) is -b/2a.
so here, b=10 and a = -1 10/-2 = -5, so C is the answer.

Answer 2

An easier way, is to take the derivative and set it equal to 0 and solve for the x coordinate.
y=x^2+10x-1
y'=2x+10
0=2x+10
x=-5
plug this into the original equation to find the y-coordinate.