What is the answer for 1+1+7x2+7y3+3+2x2−y3

First, a little housekeeping!!

1+1+7x2+7y3+3+2x2−y3 needs to be written as 1+1+7x^2+7y^3+3+2x^2−y^3.  The " ^ " signifies exponentiation and is essential here.

Now combine like terms:

7y^3-y^3   +   7x^2 + 2x^2 + 1 + 1 + 3

You'll get     6y^3 +9x^2 +  5.