The Quotient Rule for the derivative is to take the lower function and multiply it by the derivative of the upper function, then subtract from that the upper function multiplied by the derivative of the lower function, all over the lower function squared. For us that looks like this: [tex]f'(x)= \frac{x(0)-8(1)}{ x^{2} } [/tex]. Simplified that's [tex]f'(x)= \frac{-8}{ x^{2} } [/tex]. If we are evaluating that derivative at x = -1, then we have [tex]f'(-1)= \frac{-8}{(-1)^2} = \frac{-8}{1}=-8 [/tex]
