Question

Calculati valoare a expresiei:

$\frac{ a^{3} }{2 a ^{3} } * \frac{5a ^{2} }{a ^{2}+a+1 } , daca a= -3$



$\frac{a ^{2}-4 }{a ^{2}-3a+9 }: \frac{a+2}{a ^{3} +27}, daca a= 0,5$

Answer 1

(-3)³/[2·(-3)³)]·[5·(-3)²)]/[(-3)²-3+1]=
(-27)/[2·(-27)]·[5·9]/(9-3+1)=
-27/-54·45/7=
27/54·45/7=1/2·45/7=45/14



(0,5²-4)/(0,5²-3·0,5+9):(0,5+2)/(0,5³+27)=
(0,25-4)/0,25-1,5+9):2,5/(0,125+27)=
-3,75/(-0,75+9):2,5/27,125=
-3,75/8,25·27,125/2,5=
-375/100·100/825·27125/1000·10/25=simplificam ce se poate
=-5/11·217/20=-217/44=-4.93(18)