25 . выражение: a/(a^2-3a)+(a-8)/a+(7a^2-3a-72)/(a^(^3)-9a)

A/a(a-3)+(a-8)/a+(7a²-3a-72)*[a(a-3)(a+3)]=[a(a+3)+(a-8)(a²-9)/[a(a-3)(a+3)]=
=[a(a+3)+(a-8)(a-3)(a+3)+7a²-3a-72]/[a(a-3)(a+3)]=
=(a²+3a+a³-9a-8a²+72+7a²-3a-72))/[a(a-3)(a+3)]=(a³-9a)/[a(a-3)(a+3)=
=a(a²-9)/[a(a²-9)]=1