how to solve (3a squared+3a+3)+(15a squared+2a-9) need the steps on how to solve this I have to show all work

Answer 1

= (3a square+3a+3)+ (15a square+5a-9)
= (3ax3a)+3a+3)+(15ax15a)+5a-9))
= 9a sqaure+ 3a+ 3+225a square+ 5a-9
= 9a sqrare+225a square+3a+5a+3-9
=234a square + 8a - 6

Note: 3-9=-6 how?
EXAMPLE: you owed me $9 AND paid me 3. So still you owed me $ 6 and have to pay

Answer 2

adding polynomials (3g squared+2hg)+5g squared+hg-9h squared g) having alot of trouble understanding this I know you have to combine like terms first lost after that need to show all work thanks