Question

Find the maximum or minimum of the following quadratic function: y = x2 - x - 56.
A. -56
B. 56
C. -225/4
D. 225/4

Answer 1

the maximum of minimum for a quadratic lies on the line of symmetry...

your parabola is concave up... so its a minimum value

so for any quadratic

\[ax^2 + bx + c\]

the line of symmetry is

\[x = \frac{-b}{2 \times a}\]

in your question b = -1 and a = 1

so substitute them into the line of symmetry formula

when you get the value, substitute it into the original equation to get the minimum value