How to use differential equations to write $x(t)$ in terms of $y$ and $y_0$? The equations are:
$$
\left\{\begin{array}{rcrcl}
x' & = & \mbox{}-a\,x & + & b\,xy
\\
y' & = &  c\,y & - & d\,xy
\end{array}\right.
$$
They want me to write an equation for $x(t)$ in terms of $y$ and $y_0$ only.
How would I do this?

Hint: $\dfrac{dx}{dy} = \dfrac{x'}{y'}$.
