If a function f is defined by f(x)= 3/(x-1) for all non zero numbers x. If f(a) = 3 and f(ab) = 9 then b= ?  Pick
A) 1/3  B) 1/2  C) -1/2  D) -1/3  E) -2
Given that f(x) = 3/(x-1) and f(a) = 3, then f(a) =3/(x-1)=3 ===&gt; x-1=1 ==&gt; x =2, then backsolve using the answer choices:   f(ab) = f(2b) = 3/(2b-1)   1/3) 1/3 ===&gt; f(2*1/3) = f(2/3) = 3/((2*2/3)-1)= 
<gadget id="calculator">3/((2*2/3)-1)</gadget>
<output>9</output>
9 WINS   B) 1/2===&gt; f((2*1/2) = f(1) = 3/1-1 = undefined   C) -1/2 ===&gt; f(2*-1/2) = f(-1) = 3/1+1 = 3/2   D) -1/3 ===&gt; f(2*-1/3) = f(-2/3) = 3/(2*-2/3 -1) = -9/7   E) -2 ===&gt; f(2*-2) = f(-4) = 3/(2*-4 -1) = -1/3   1/3nswer: 1/3
<result>A</result>
If a function f is defined by f(x)= 3/(x-1) for all non zero numbers x. If f(a) = 3 and f(ab) = 9 then b= ?