Hi!
Your answer is [tex]5x^2-7x-8[/tex].
We are asked:
[tex](-3x^2-5x+1)+(8x^2-2x-9)[/tex]
As we are adding them, we can remove the parenthesis.
[tex]-3x^2-5x+1+8x^2-2x-9[/tex]
Now, we can switch the order of the terms around to cause like terms to be by each other:
[tex]-3x^2+8x^2-5x-2x+1-9[/tex]
Finally, add like terms:
[tex]5x^2-7x-8[/tex]
