Question

найдите значение выражения

Answer 1

1)a²-3a-1/a+3=(a³-3a²-1+3a)/a=(a-1)³/a
2)(a-1)³/a *1/[(a-1)(a+1)]*a(a+1)(a-1)²
a=2,5  (2,5-1)²=1,5²=2,25

Answer 2

$(a^2-3a- frac{1}{a}+3 ) frac{1}{a^2-1} (a^2+a)=(a^3-3a^2+3a-1)a(a+1) frac{1}{a(a^2-1)} =$
$frac{(a-1)^3(a+1)}{(a-1)(a+1)} = (a-1)^2 = 1.5^2=2.25$