Answer:
First trinomial:
[tex]5x+6y+7[/tex]Second trinomial:
[tex]2x+y+1[/tex]Sum:
[tex]7x+7y+8[/tex]Difference:
[tex]3x+5y+6[/tex]Step-by-step explanation:
Let our first trinomial be:
[tex]5x+6y+7[/tex]And let our second trinomial be:
[tex]2x+y+1[/tex]The sum would be:
[tex]\begin{gathered} 5x+6y+7+(2x+y+1) \\ \rightarrow5x+6y+7+2x+y+1 \\ \\ \Rightarrow7x+7y+8 \end{gathered}[/tex]And the difference would be:
[tex]\begin{gathered} 5x+6y+7-(2x+y+1) \\ \\ \rightarrow5x+6y+7-2x-y-1 \\ \\ \Rightarrow3x+5y+6 \end{gathered}[/tex]