2. Let

$$
\sqrt{25-a^{2}}-\sqrt{9-a^{2}}=3
$$

Calculate the value of the expression

$$
\sqrt{25-a^{2}}+\sqrt{9-a^{2}}
$$
Answer: $16 / 3$.

Solution. Let

$$
\sqrt{25-a^{2}}+\sqrt{9-a^{2}}=x
$$

Multiplying this equality by the original one, we get $16=3 x$.

Evaluation. Full solution score: 11 points.