Question

Find the derivative of f(x) = negative 10 divided by x at x = -12.

Answer 1

$f(x)=\dfrac{10}{x};\ D:x\neq0\\\\f'(x)=-\dfrac{10}{x^2}\\\\x=-12\to f'(-12)=\dfrac{-10}{(-12)^2}=\dfrac{-10}{144}=-\dfrac{5}{72}$