Question

Given the parabola f(x)=x^2+4x+21, state and Identify the max or min value.

Answer 1

f(x) = x^2 + 4x + 21
f'(x) = 2x + 4
f''(x) = 2 > 0 (min)

For min value,
f'(x) = 0
2x = -4
x = -2

f(-2) = 4 - 8 + 21 = 17