Question

How do you find the axis of symmetry, and the maximum or minimum value of the function `f(x) = 2x^2 + x - 3`?

Answer 1

Min `(-1/4, -25/8)`

Explanation:

`f(x) = 2x^2 + x - 3`
x- coordinate of axis of symmetry:
`x = -b/(2a) = -1/2 = - 1/4`
Because a = 2 > 0, the parabola opens upward. There is a min.
To find the Min, replace x by (-1/4) in f(x).
`f(-1/4) = 1/8 - 1/4 - 3 = - 1/8 - 3 = - 25/8`
Min `(-1/4, -25/8)`