If a function f is defined by f(x)= -1/x for all non zero numbers x. If f(a) = -1/3 and f(ab) = 1/6 then b= ?  Choose the correct choice.
A) 2	B) 1/2	C) -1/2	D) -2	E) -12
f(a) = -1/3 = -1/a, and thus a = 3   f(ab) = 1/6, and thus ab = -6   3b = -6   b = -2   The answer is -2.
<result>D</result>
If a function f is defined by f(x)= -1/x for all non zero numbers x. If f(a) = -1/3 and f(ab) = 1/6 then b= ?