Consider the following expression and the simplified expression. Expression
Simplified Expression
3 x squared + 5 y squared box + 3 box + 4 y squared + 6
9 x squared minus y squared + 9

Which terms could be in the boxes to make the expressions equivalent?
Positive 6 x squared and Negative 6 y squared
Positive 6 x squared and Negative 10 y squared
Positive 9 x squared and Negative 10 y squared
Positive 9 x squared and Negative 6 y squared