Метод рационализации

$$ \log_a f $$	$$ (a-1)(f-1) $$
$$ \log_a f - \log_a g $$	$$ (a-1)(f-g) $$
$$ \log_f h - \log_g h $$	$$ (f-1)(g-1)(h-1)(g-f) $$
$$ h^f-h^g $$	$$ (h-1)(f-g) $$
$$ f^h-g^h $$	$$ h(f-g) $$
$$ \|f\|-\|g\| $$	$$ (f-g)(f+g) $$