Answer:
[tex]C.)3x^3+10x^2y+3xy^2-3xy-y^2[/tex]Explanation:
Given the multiplication expression:
[tex](x^2+3xy-y)\mleft(3x+y\mright)[/tex]On expansion:
[tex]\begin{gathered} =x^2(3x)+x^2y+3xy(3x)+3xy(y)-3xy-y^2 \\ =3x^3+x^2y+9x^2y+3xy^2-3xy-y^2^{} \end{gathered}[/tex]Take the sum
[tex]=3x^3+10x^2y+3xy^2-3xy-y^2[/tex]This gives the required product.