Верхний пример упростите❤️

Решите задачу:

$1)\frac{s^{2}-4s+16 }{16s^{2}-1 }*\frac{4s^{2}+s }{s^{3}+64 }=\frac{(s^{2}-4s+16)*s*(4s+1) }{(4s+1)(4s-1)*(s+4)(s^{2}-4s+16)} =\frac{s}{(4s-1)(s+4)}\\\\2)\frac{s}{(4s-1)(s+4)}-\frac{s+4}{4s^{2}-s }=\frac{s}{(4s-1)(s+4)}-\frac{s+4}{s(4s-1)}=\frac{s^{2}-s^{2}-8s-16}{s(4s-1)(s+4)}=\frac{-8(s+2)}{s(4s-1)(s+4)}$

$3)\frac{-8(s+2)}{s(4s-1)(s+4)}:\frac{4}{s^{2}+4s }=\frac{-8(s+2)}{s(4s-1)(s+4)}*\frac{s(s+4)}{4}=\frac{-2(s+2)}{4s-1}\\\\4)\frac{-2(s+2)}{4s-1}-\frac{20s+13}{4-16s}=\frac{-2s-4}{4s-1}+\frac{20s+13}{4(4s-1)}=\frac{-8s-16+20s+13}{4(4s-1)}=\frac{12s-3}{4(4s-1)}=\frac{3(4s-1)}{4(4s-1)}=\frac{3}{4}=0,75$