Question 951032

If {{{ f(x) = 2sqrt (x) }}} and {{{ g(x) = 2+2x }}} find the exact value of:

{{{ f(f(81)) }}}

{{{ f(81)=2sqrt (81) }}}

{{{ f(81)=2*9 }}}

{{{ f(81)=18 }}}

{{{ f(f(81))=f(18) }}}

{{{ f(f(81))=2sqrt (18) }}}

{{{ f(f(81))=2sqrt (2*9) }}}

{{{ f(f(81))=2*3sqrt (2) }}}

{{{ f(f(81))=6sqrt (2) }}}