Question

Dauuuuuu coroanaaaa va roggg ajutati-ma!
Media geometrica a numerelor a si b este egala cu 4√5.
Daca a=7-3√5, determinati numarul b si media aritmetica a numerelor a si b.

Answer 1

[tex]m_{g}=\sqrt{a*b}\\ 4\sqrt{5}=\sqrt{a*b}\\ 80=a*b\\ (7-3\sqrt{5})*b=80\\ b=\frac{80}{7-3\sqrt{5}}\\ b=\frac{80(7-3\sqrt{5})}{4}\\ b=20(7-3\sqrt{5})\\ m_{a}=\frac{a+b}{2}\\ m_{a}=\frac{20(7-3\sqrt{5})+7-\sqrt5}{2}\\ m_{a}=\frac{21(7-3\sqrt5)}{2}[/tex]

Answer 2

b=140+60√5
Ma=(7-3√5+140+60√5):2
Ma=(147+57√5):2  si o scrii sub forma de fractie, exercitiul e corect iti garantez