Sorry about previous post,

The information I have is that I have to an expression for a slope of a curve.

I know that the slope of the curve is $\displaystyle \frac{-dy}{dx}$

$\displaystyle \frac{-dy}{dx} = \frac{-4x+4y+64}{4x-8y+32} = 0$

I reach this point, and I seem to fail to understand what I’m supposed to do, my method is that the

$\displaystyle \frac{-4x}{4x}$ cancels to leave $\displaystyle - x$

$\displaystyle \frac{4y}{-8y}$ gets $\displaystyle -0.5y$

$\displaystyle \frac{64}{32}$ gets $\displaystyle 2$

Rearranging then gets you

$\displaystyle \frac{-dy}{dx} = 2-x-0.5y$

Which would be the expression for my slope?