Page 126 - Algebra

Worked Example
Find the maxima or minima of f(x) = x2 – 10x + 21
Solution:
Here a > 0, so the function has a minima a = 1, b = – 10, c = 21
−𝑏 x = 2𝑎
Put f(5) in
x = –4
x= –
–10 2
= 5
x2 – 10x + 21
52 –10(5)+21=0
25 – 50 + 21= 0
The minima of the function is –4
The coordinates are (5, –4)
Page 125 of 177
Algebra I & II