Hello Naunherimerin. To find the side of a cube with a volume of 520 we can use the cube root since it is the opposite of a cube^3 So lets do that real fast.
[tex]V = s^3[/tex]
Cube both sides
[tex]520 = s^3[/tex]
[tex]\sqrt[3]{520} = \sqrt[3]{s^3}[/tex]
[tex]\sqrt[3]{520} = s[/tex]
[tex]2\sqrt[3]{65} = s[/tex]
[tex]s = 2\sqrt[3]{65} = 8[/tex]