# How do you simplify  x^5y + x^4y^2 - 3x^5y + 9x^4y^2 - 2x^4y^2?

$= \left({x}^{5} y - 3 {x}^{5} y\right) + \left({x}^{4} {y}^{2} + 9 {x}^{4} {y}^{2} - 2 {x}^{4} {y}^{2}\right) = - 2 {x}^{5} y + 8 {x}^{4} {y}^{2}$