Find the range of the function f(x) = x² + 3

The range of a function is the set of all its outputs.

Answer: The range of f(x) = x² + 3 is [3, ∞).

We will make use of the concept of the domain of the function to find the range of f(x). 

Explanation:

We have the function f(x) = x² + 3.

The domain of the function is the set of real numbers (R).

f(x) is an upward-opening parabola with a bottom at (0, 3). Hence, f(x) takes all positive values, including 3 at x = 0. 

Thus, the range of f(x) = x² + 3 is [3, ∞).