The answer is:
[tex](-x^{2}+9)+(3x^2-11x+4)=2x^{2}-11x+13[/tex]
To solve the problem, we must remember how to add/subtract like terms. The like terms are the terms that share the same variable and the same exponent.
For example:
[tex]2x+3x+x^{2}=x^{2}+(2x+3x)=x^{2}+5x[/tex]
We were able to add only the linear terms (terms that contains the variable x") because they were like terms: they share the same variable and the same exponent.
We need to perform the following operation between polynomials:
[tex](-x^{2}+9)+(3x^2-11x+4)[/tex]
So, calculating we have:
[tex](-x^{2}+9)+(3x^2-11x+4)=2x^{2}-11x+13[/tex]
Have a nice day!