Let the function \displaystyle ff be defined by \displaystyle f\left(x\right)=x^{2}+12f(x)=x 2 +12. If \displaystyle nn is a positive number such that \displaystyle f\left(3n\right)=3f\left(n\right)f( 3n)=3f(n), what is the value of \displaystyle nn?

A33 gram sample of a substance that's used to detect explosives has a k-value of 0.1473. n = noekt no = initial mass (at time t = 0) n = mass at time t k = a positive constant that depends on the substance itself and on the units used to measure time t = time, in days