To find the constant terms in the expression \( 6x^2 + 7xy + 3 + 9 \), we need to identify the terms that do not contain any variables (like \( x \) or \( y \)).
In the expression:
- \( 6x^2 \) is a term with the variable \( x \).
- \( 7xy \) is a term with variables \( x \) and \( y \).
- \( 3 \) is a constant term.
- \( 9 \) is also a constant term.
Now, we can add the constant terms together: \[ 3 + 9 = 12. \]
Therefore, the constant terms in the expression are \( 3 \) and \( 9\), and their sum is \( 12 \).