6x7

(a)  

8x6

(a)  

7x5

(a)  

8x8

(a)  

2x0

(a)  

6x6

(a)  

2x2

(a)  

5x6.

(a)  

6x2.

(a)  

7x8

(a)  

3x6.

(a)  

9x3.

(a)  

5x8

(a)  

6x6.

(a)  

4x2.

(a)  

8x8.

(a)  

9x8

(a)  

7x9

(a)  

9x6

(a)  

2x6

(a)