Question

Se F(x) = x^2-4/x-1 achar F(1/t)

Answer 1

$f(x)= \frac{ x^{2} -4}{x-1}$
$f( \frac{1}{t} )= \frac{ (\frac{1}{t})^{2} -4}{ \frac{1}{t} -1}$
$f( \frac{1}{t} )= \frac{ \frac{1}{t^2} -4}{ \frac{1}{t} -1}$
$f( \frac{1}{t} )= \frac{ \frac{1-4t^2}{t^2} }{ \frac{1-t}{t} }$
$f( \frac{1}{t} )= \frac{1-4t^2}{t^2}}x \frac{t}{1-t}$
$f( \frac{1}{t} )= \frac{t-4t^3}{t^2-t^3}$
$f( \frac{1}{t} )= \frac{t(1-4t^3)}{t^2(1-t)}$
$f( \frac{1}{t} )= \frac{1-4t^2}{t(1-t)}$