Answer:
Step-by-step explanation:
Please use " ^ " to denote exponentiation: f(x) = x^2 + 4x - 21.
This function has a graph which is a parabola that opens up.
Its vertex is found by completing the square:
x² + 4x + 4 - 4 - 21, or
(x + 2)² - 25
Comparing this to the standard equation
(x - h)² + k, we see that h = -2 and k = -25.
Thus, the vertex (and the minimum of this function) is (-2, -25).
Thus, the range is [-25, ∞ ). This being a polynomial function, it has no restrictions on the domain: the domain is (-∞, ∞ )
