ДАЮ 40 БАЛЛОВ! Помогите

Question

ДАЮ 40 БАЛЛОВ! Помогите

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Answer 1

A+1/a=3
a)a²+1/a²=(a+1/a)²-2=3²-2=9-2=7
б)(a^4+1)/2a²=1/2(a²+1/a²)=1/2*7=7/2=3,5
в)(a^8+1)/a^4=(a^4+1/a^4=(a²+1/a²)²-2=7-2=5
г)a³+1/a³=(a+1/a)(a²-1+1/a²)=3*(7-1)=3*6=18