Find the domain and the range of f(x) = √(25 - x²).

Step 1. The domain. $25 - x^2 \geq 0$ gives $-5 \leq x \leq 5$: the domain is $[-5, 5]$.

Step 2. The range. $25 - x^2$ runs from $0$ (at $x = \pm 5$) up to $25$ (at $x = 0$). Its root runs from $0$ to $5$.