Diketahui n(A x B) = (n(A) + 1)(n(B) - 3) dan n(B) = 7. Jika n(A x B) = 36, maka n(A) = . . . . . ????

n(A X B) = (n(A) + 1)(n(B) - 3) dan n(B) = 7
36         =(n(A) + 1) (7 - 3)
36          =(n(A + 1) (4)
36/4        =n(A) + 1
9            =n(A) + 1
9 - 1        =n(A)
8            n(A)

n(AxB)= (n(A)+1)(n(B)-3)
dimisalkan n(A) = p
maka :

36 = (p + 1) (7-3)
36 = (p+1) (4)
36 = 4p + 4
36-4 4p
32/4 = p
p = 8