Suppose that $X,Y$ are random variables, and that I define:
$$ T_1 = \frac{N_1X}{K_1^2}+ \frac{N_2Y}{K_2^2} $$
and
$$ T_2 = \frac{N_1}{2K_1^2}+ \frac{N_2}{2K_2^2} $$
where $N_1, N_2, K_2, K_2$ are constants.
I am wondering if it is possible to define a function $f(T_1, T_2)$ such that $f(T_1, T_2) = T_1- XT_2$? It seems that no matter what, I have to define the function to be a function of a random variable, which nullifies it?