Respuesta :

XxitzmeyanyanxX

[tex] \: \: \: \: \: [/tex]

first add

(3a²-5a+5)+(a³-5a²+8)

=3a²-5a+5+a³-5a²+8

=a³-2a3a²-5a²+5+8

=a³-2a²+13

and now,

substract a³-2a²+13 from a²-4a²-9

=7a²-4a²-9-(a³+13)

=7a²-4a²-9-a³+2a²-13

= a³+7a²-4a²+2a²-9-13

=-a³+5a²-22

hope it helps