Question

Por favor me ajudem, eu não estou entendendo esse conteúdo

Answer 1

$\frac{3y-4}{y^2-16} - \frac{1}{y-4}=\\\\ \frac{3y-4}{(y-4)(y+4)} - \frac{1}{y-4}=\\\\ \frac{(3y-4)-(y+4)}{(y-4)(y+4)}= \\\\ \frac{(3y-4-y-4)}{(y-4)(y+4)}= \\\\ \frac{2y-8}{(y-4)(y+4)}= \\\\ \frac{2(y-4)}{(y-4)(y+4)}= \\\\ \frac{2}{y+4}$