Ayuda por favor son sumas y restas de polinomios

1- (4a-5ab)+(12b+15a)-(17ab-8b)


2- x^3 y+(8xy^3-20x^3 y)-(25xy^3-20y^3 x)+yx^3


3- (b+b^2 )+(3b^2-4)+(3b-4b^3 )


4- (3+5n-2n^3 )+(3n^3+n-4)-(4n^2-2n^2 )


5) (1/2 m-m^2+1/5 m^3 )+(-1/2 m+4/5 m^2-1/10 m^3