By what factor the velocity of a body should be increased so that its Kinetic energy is increased by a factor of nine

Kinetic energy is equal to 1/2m speed ^2 
so let speed be x 
energy=1/2m x^2 
Now speed =3x 
then new energy=1/2m (3x)^2 
=1/2 m 9 (x)^2 
Energy becomes 9 times the former energy