Solving following System of ordinary differential equations. How to solve system of ODEs which contains independent variable like t in equation as in this particular case : 
$$\frac{dx}{dt}= -x + ty $$ $$ \frac{dy}{dt} = tx-y$$ can we solve them or additional information may be needed (may be about t) ?

Hint...you can subtract the equations and write $u=y-x$ to obtain a seperable variable DE in $u$ and $t$
