Is this correct?

The problem says perform the indicated operation.

(9x^2-7x-66)+(8x^2+9x)

I came up with this for the answear
-66+2x+17x^2

or could it be

17x^2+2x-66

To solve this problem, you need to combine like terms by adding or subtracting coefficients of the same degree.

Let's look at each step in detail:

Step 1: Rewrite the given expression:
(9x^2-7x-66)+(8x^2+9x)

Step 2: Combine the terms with the same degree:
(9x^2 + 8x^2) + (-7x + 9x) - 66

Step 3: Simplify the coefficients:
17x^2 + 2x - 66

So, the correct answer is:
17x^2 + 2x - 66

Your second suggestion, 17x^2+2x-66, is the correct simplified form of the given expression. Well done!