1. Simplify the expression completely: $8\sqrt{6} + 5\sqrt{6} - 2\sqrt{6} = \_\_\_$.
2. Which expression is the simplified form of $5\sqrt{3k} + 8\sqrt{2m} - 2\sqrt{3k}$?
3. Simplify the expression by first simplifying the radicals: $2\sqrt{75} - 4\sqrt{3} = \_\_\_$.
4. Which of the following expressions cannot be simplified further by combining terms?
5. Simplify the following expression: $\frac{10\sqrt{5x}}{7} - \frac{4\sqrt{5x}}{7} + \frac{9\sqrt{2y}}{7} = \_\_\_$.
6. Which of the following pairs contains like radicals?
7. Simplify the expression by combining like radicals: $10\sqrt{3} + 5\sqrt{7} - 4\sqrt{3}$. The simplified form is ___.
8. Which radical is a 'like radical' to $4\sqrt{m^2n}$? (Assume $m$ and $n$ are positive).
9. Simplify the expression: $9\sqrt{2} - 4\sqrt{5} + 6\sqrt{2} + 7\sqrt{5}$. The simplified form is ___.
10. Why can't the expression $8\sqrt{6} + 2\sqrt{11}$ be simplified further?