Copy the Diamond Problems below and complete each of them. The pattern used in the Diamond Problems is shown below.

1. 

   Hint (a):

   $(3a)(7)$
   $3a + 7$

   Answers (a):

   

2. 

   Hint (b):

   $(?)(3x) = 12x$

   Answers (b):

   

3. 

   Hint (c):

   $? + 2y = 2y − 6$

   Answer (c):

   

4. 

   Hint (d):

   $(3y)(?) =-6y$