Ответ:

20 /(4-t^2)

Объяснение:

(t^2−64)/(t+2) ⋅ 1/(t^2+8t) − (t+8)/(t^2−2t) =

(t+8)*(t-8)/(t+2) ⋅ 1/(t*(t+8)) − (t+8)/(t*(t−2)) =

(t-8)/((t+2)*t) − (t+8)/(t*(t−2)) =

(t-8)*(t−2)/(t+2)*t*(t−2) − (t+8)*(t+2)/(t+2)*t*(t−2) =  

(t^2 + 16 - 2t - 8t - t^2 - 16 -2t - 8t)/t * (t^2 -4) =

- 20/(t^2 -4) =

20 /(4-t^2)

у меня так..