if f(f(X))=81. then. value of x=?
when f(X)=2X-1+f(X-1). is not equal to zero and f(X=0)=0	Choose the correct choice from the following answers
A) 2  B) 3  C) 4  D) 5  E) 6
f(X=0) = 0   f(X=1) = 2*1-1+f(1-1)   = 2-1+0= 
<gadget id="calculator">2-1+0</gadget>
<output>1</output>
1   f(X=2) = 2*2-1+f(2-1)   = 4-1+1   2*2-1+ (2-1)= 
<gadget id="calculator">2*2-1+ (2-1)</gadget>
<output>4</output>
4-1+1= 
<gadget id="calculator">4-1+1</gadget>
<output>4</output>
4   f(X=3) = 2*3-1+f(3-1)   = 6-1+4= 
<gadget id="calculator">6-1+4</gadget>
<output>9</output>
9===&gt;f(X=n) = n^2   f(f(X)) = 81   X = sqrt(sqrt(81)) = 3   ANSWER:3
<result>B</result>
if f(f(X))=81. then. value of x=?
when f(X)=2X-1+f(X-1). is not equal to zero and f(X=0)=0