Question

Упростите выражение:
$frac{a+4}{ a^{2}-6a+9 }$÷$frac{a^{2}-16 }{2a-6}$-$frac{2}{a-4}$

Answer 1

$frac{a+4}{(a-3)(a-3)} * frac{2(a-3)}{(a-4)(a+4)} - frac{2}{a-4}= frac{2}{(a-3)(a-4)}- frac{2}{a-4}= frac{2-2(a-3)}{(a-3)(a-4)}=$
$frac{2-2a+6}{a^{2}-7a+12}$=$frac{4-2a}{a^{2}-7a+12 }$