Simplify:

(1/5x^4+1/3xy^2+1/2y^2)+(6/5x^2y^2+2xy^2+11/6y^2)

Assuming you meant

(1/5 x^4+1/3 xy^2+1/2 y^2)+(6/5 x^2y^2+2xy^2+11/6 y^2) just add like-power terms:

1/5 x^4 + 6/5 x^y^2 + 7/3 xy^2 + 7/3 y^2