Direct variation

Question

If y varies directly proportional to the 5/2 power of x, by what factor will y change when x is tripled?

Answer 1

y = kx^5/2

 

y = k (3x)^5/2  gives the same k and the same x^5/2 but has the extra factor 3^2.5 which is 3²√3 = 9(1.732050808)

WHICH IS AN OVERALL FACTOR OF 15.588, APPROXIMATELY.