6

43

-5

3

--------

(a)  

67

-6

9

4

--------

(a)  

78

-6

9

8

-------

(a)  

46

9

-5

7

-------

(a)  

47

-5

8

2

--------

(a)  

8

79

9

-5

--------

(a)  

83

9

-1

7

-------

(a)  

67

9

-5

6

--------

(a)  

76

9

-3

7

-------

(a)