To solve the expression $2\sqrt{2} + 5\sqrt{9}$:

1. Simplify the square roots:

   • $\sqrt{2}$ remains $\sqrt{2}$ because it's already in its simplest form.
   • $\sqrt{9} = 3$ because $9 = 3^2$.

2. Substitute the simplified values back into the expression: $2\sqrt{2} + 5\sqrt{9} = 2\sqrt{2} + 5 \times 3$

3. Multiply $5$ by $3$: $5 \times 3 = 15$

4. Combine the terms: $2\sqrt{2} + 15$

So, the simplified expression is $2\sqrt{2} + 15$.

Would you like more details or have any questions?

Here are some related questions to expand on this concept:

1. What is $3\sqrt{2} + 4\sqrt{9}$?
2. How do you simplify $\sqrt{18} + 2\sqrt{8}$?
3. What is $2\sqrt{2} + 3\sqrt{4}$?
4. If you have $7\sqrt{5} + 2\sqrt{25}$, what is the result?
5. How do you add $2\sqrt{2} + 5\sqrt{8}$?
6. What is $4\sqrt{3} + 2\sqrt{27}$?
7. How do you simplify $\sqrt{50} + 5\sqrt{2}$?
8. What is $3\sqrt{11} + 2\sqrt{99}$?

Tip: When simplifying expressions with square roots, always simplify the square roots first before performing any other operations.