Question

Find the maximum or minimum of the following quadratic function: y =x2 - 10x + 25.

A. 0
B. 25
C. -25
D. 50

Answer 1

differentiation?
maxima and minima?

Answer 2

this is a perfect square,

y = (x - 5)^2

it contacts the x axis at 1 point, which will be the minimum.

all you need to do is solve

x - 5 = 0

to find the point of contact...

substitute to find y, the minimum value.

Answer 3

\[\frac{ dy }{ dx} = 2x - 10\]
when you equal the first derivative with 0 you get: 2x -10 = 0 and x = 5
your function has the minimum value in x = 5 and the value is y = 25 - 50 + 25 = 0