Respuesta :

-3 + 13x + 3y + y^2  
*Im not sure if my math is correct, hope its right and helps you a lot! :)*
What is did to solve this problem was i wrote this down to get this figured out. 
7x + 3y - 2 + 6x - 1 + y^2 

The first thing I did to this problem was i took 6x and change it to a -6x because I'm subtracting it from 7x which 7x - 6x is just x cause there is an understood 1 next to it. So i rewrote the problem as x + 3y - 2 - 1 + y^2

So then i took the -2 and subtract it to 1 which is -3

So the answer I have is x+3y-3+y^2 

Hope this helped! :)

~ShadowKitty101