Question

si:f(a)=a+2/a-2 . Halle f(f(a))

Answer 1

$f(a) = \frac{a + 2}{a - 2} \\ \\ f(f(a) ) = \frac{ \frac{a + 2}{a - 2} + 2}{ \frac{a + 2}{a - 2} - 2} \\\\ f(f(a) ) = \frac{ \frac{a + 2 + 2(a - 2)}{a - 2} }{ \frac{a + 2 - 2(a - 2)}{a - 2} } \\\\ f(f(a) ) = \frac{ \frac{a +2 + 2a - 4}{a - 2} }{ \frac{a + 2 - 2a + 4}{a - 2} } \\\\ f(f(a) ) = \frac{ \frac{3a - 2}{a - 2} }{ \frac{ - a + 6}{a - 2} } \\\\f(f(a) ) = \frac{3a - 2(a - 2) }{ -a + 6(a - 2)} \\\\ f(f(a) ) = \frac{3a - 2}{ - a + 6}$