To find the total cost \( y \) to print 200 invitations using the equation provided:
\[ y = 3.12x + 3.30 \]
Substituting \( x = 200 \) into the equation:
\[ y = 3.12(200) + 3.30 \]
Calculating \( 3.12 \times 200 \):
\[ 3.12 \times 200 = 624 \]
Now we can add the setup cost of $3.30:
\[ y = 624 + 3.30 \]
Now, calculating the total:
\[ y = 627.30 \]
Therefore, it will cost Betty \( \text{$627.30} \) to print 200 invitations.