Answer:
f(x) has a minimum value of -10.
Explanation:
It will have a minimum value because the coefficient of x^2 is positive.
To find its value we convert to vertex form:
f(x) = 4x^2 - 16x + 6
= 4(x^2 - 4x) + 6
= 4[(x - 2)^2 - 4] + 6
= 4(x - 2)^2 - 16 + 6
= 4(x - 2)^2 - 10.
So the minimum value is -10.