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) = 1/9 then b= ?	Pick one:
A) 1/6.	B) -1/3.	C) 1/3.	D) -3.	E) 12.
f(a) = -1/3 = -1/a, and thus a = 3   f(ab) = 1/9, and thus ab = -9   3b = -9   b = -3   The answer is -3..
<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) = 1/9 then b= ?