Simplify 7√99 .

We can start by breaking down √99 into its prime factors:

√99 = √(9 * 11)

Next, we can simplify the square root of 9:

√(9 * 11) = √9 * √11 = 3√11

Finally, we can multiply 7 by 3√11:

7 * 3√11 = 21√11

Therefore, the simplified form of 7√99 is 21√11.