Question

помогите пожааалуйста​

Answer 1

$\frac{z}{(z+10)^{2}} -\frac{z}{z^{2}-100}=\frac{z}{(z+10)^{2}} -\frac{z}{z^{2}-10^{2}}=\frac{z}{(z+10)^{2}} -\frac{z}{(z-10)(z+10)}=\frac{z*(z-10)-z(z+10)}{(z+10)^{2}(z-10)}=\\\\=\frac{z^{2}-10z-z^{2}-10z}{(z+10)^{2}(z-10)}=-\frac{20z}{(z+10)^{2}(z-10)}\\\\Otvet:\boxed{(z+10)(z+10)(z-10)}$