Question

(Z^2-4z-21)/(z^2-6z-7)

Answer 1

$\frac{z^{2}-4z-21 }{z^{2}-6z-7 }=\frac{(z+3)(z-7)}{(z+1)(z-7)}=\frac{z+3}{z+1}\\\\Otvet:\boxed{\frac{z+3}{z+1}}$