Answer
$24x^3y^2+x^2y-12x^2+4$; degree is $5$
Work Step by Step
Start by breaking down the parentheses. Then combine like terms to simplify. The degree is the combined powers of the highest exponents if there are two variables.
$(13x^3y^2-5x^2y-9x^2)-(-11x^3y^2-6x^2y+3x^2-4)$
$13x^3y^2-5x^2y-9x^2+11x^3y^2+6x^2y-3x^2+4$
$24x^3y^2+x^2y-12x^2+4$