Simplify:

9 sqrt5 -3 sqrt5

To simplify the expression 9√5 - 3√5, we can combine like terms.

Both terms have the same radical, which is √5.

When we combine the coefficients (numbers in front of the radical), we have 9 - 3 = 6.

So, the simplified expression is 6√5.

To solve it manually, you can follow these steps:

Step 1: Identify the radical in the expression. In this case, the radical is √5.

Step 2: Combine the coefficients (numbers in front of the radical) of the terms. In this case, we have 9 and -3, so 9 - 3 = 6.

Step 3: Rewrite the expression with the simplified coefficient and the radical. The result is 6√5.