Evaluate \acf(x)−f(a)x−a\ac{f(x) - f(a)}{x-a}\acf(x)−f(a)x−a for f(x)=1/xf(x) = 1/xf(x)=1/x and simplify.
−1/ax-1/ax−1/ax
1/ax1/ax1/ax
1/(x−a)1/(x-a)1/(x−a)
−1/(x−a)-1/(x-a)−1/(x−a)