Question

1. Without graphing find the vertex and axis of symmetry. Indicate if the vertex is a

max or minimum.
y= -2x2+8x-3

Answer 1

the vertex is at (2, 5) and the axis of symmetry is x = 2

Explanation:

A word to the wise: Please use " ^ " to indicate exponentiation. And so we have:

y= -2x^2+8x-3

The x-coordinate of the vertex and the equation of the axis of symmetry is determined by the equation

b -8

x = ------- which here is x = ----------- = 2

2a 2(-2)

Then the y-coordinate of the vertex is f(2) = -2(-2)^2 + 8(2) - 3 = 8 - 3 = 5

and so the vertex is at (2, 5) and the axis of symmetry is x = 2