Solve by completing the square with working out

-6x-x^2-8

x = -3 +/- sqrt(17)

Step-by-step explanation:

-6x - (x^2) - 8 = 0

-((x^2) + 6x + 8) = 0

(x^2) + 6x + 8 = 0

(x + 3)^2 - 1 = 0

(x + 3)^2 = 1

x + 3 = +/- sqrt(1)

x + 3 = +/- 1

x = -3 +/- 1

x = -4, -2

if the eqn of the parabola is f(x) = (x-4)(x+2), we need to mult. this out to find the coordinates of the vertex.

then f(x) = x^2 + 2x - 4x - 8, and f(x) = x^2 - 2x - 8.

one way in which you can find the vertex is to calculate x = -b / (2a).   here, that comes to

        )

x = = 1.   f(1) = 1^2 - 2(1) - 8 = - 9.   vertex is at (1, -9).

        2(1) 

find another point on the curve:   let x=0, for which y=-8.   then (0, -8) is on the curve.   plot the vertex and this point and draw a smooth parabola thru both.

hope this