Answer C : 3x^2+7xy-2y^2
equivalent to the following expression
[tex](2x^2+4xy-y^2)+(x^2+3xy-y^2)[/tex]
[tex]2x^2+4xy-y^2+x^2+3xy-y^2[/tex]
Combine like terms
[tex]2x^2+x^2+4xy+3xy-y^2-y^2[/tex]
2x^2 + x^2 is 3x^2
4xy+3xy is 7xy
-y^2-y^2 is -2y^2
So expression becomes
[tex]3x^2+7xy-2y^2[/tex]
Answer C is correct
