3x2

(a)  

6x2

(a)  

8x2

(a)  

10x2

(a)  

9x2

(a)  

2x9

(a)  

2x3

(a)  

7x2

(a)  

2x5

(a)  

2x4

(a)  

1x2

(a)  

2x1

(a)