Question

How do you write a specific formula to describe the variation:x varies directly with the cube root of y; x=3 when y = 125?

Answer 1

The variation formula may be written as `125x^3=27y`

Explanation:

`x prop root(3)y or x =k * root(3)y` ; k= constant of proportionality
`x =3` when `y =125 :. 3 =k* root(3)125 or 3=k*5 or k=3/5` So the variation formula may be written as `x= 3/5*root(3)y or x^3 =27/125*y or 125x^3=27y`[Ans]