Question

люди добрые, помогите​

Answer 1

$1)\frac{a^{3}-1 }{2a^{3}} *\frac{5a^{2}}{a^{2}+a+1 } =\frac{(a-1)(a^{2}+a+1)*5a^{2}}{2a^{3}*(a^{2}+a+1)}=\frac{5(a-1)}{2a}\\\\a=-3\\\\\frac{5(a-1)}{2a} =\frac{5(-3-1)}{2*(-3)}=\frac{5*(-4)}{-6}=\frac{-20}{-6}=3\frac{1}{3}\\\\Otvet:\boxed{3\frac{1}{3}} \\\\\\2)\frac{a^{2}-4 }{a^{2}-3a+9 }:\frac{a+2}{a^{3}+27 }=\frac{(a+2)(a-2)}{a^{2}-3a+9}*\frac{(a+3)(a^{2}-3a+9)}{a+2}=(a-2)(a+3)\\\\a=0,5\\\\(a-2)(a+3)=(0,5-2)(0,5+3)=-1,5*3,5=-5,25\\\\Otvet:\boxed{-5,25}$