Answer 1

\(\sqrt{\left(2,5\right)^2}=\left|2,5\right|=2,5=\dfrac{5}{2}\)

\(\sqrt{\dfrac{64}{25}}=\sqrt{\left(\dfrac{8}{5}\right)^2}=\left|\dfrac{8}{5}\right|=\dfrac{8}{5}=1,6\)

Answer 2

√6425=√(85)2=∣∣∣85∣∣∣=85=1,6

Answer 3

\(a,\sqrt{\left(2,5\right)^2}=^2\sqrt[]{2,5^2}=2,5=\dfrac{5}{2}\) 

\(b,\sqrt{\dfrac{64}{25}}=\dfrac{\sqrt{64}}{\sqrt{25}}=\dfrac{\sqrt{8^2}}{\sqrt{5^2}}=\dfrac{8}{5}=1,6\)