# When will the slope field for the differential equation (2x)/(4y-xy) have vertical segments?

I’m assuming the differential equation is $\frac{\mathrm{dy}}{\mathrm{dx}} = \frac{2 x}{4 y - x y}$
We know that slope will be vertical when $\frac{\mathrm{dy}}{\mathrm{dx}}$ is undefined.
This will occur when $4 y - x y = 0 \to y \left(4 - x\right) = 0 \to y = 0 \mathmr{and} x = 4$