$$\lim_{x \to 4^-}\left(x - \frac{2}{x}\right) = \frac{7}{2}$$ More at x→4 from the left $$\lim_{x \to 4^+}\left(x - \frac{2}{x}\right) = \frac{7}{2}$$ $$\lim_{x \to \infty}\left(x - \frac{2}{x}\right) = \infty$$ More at x→oo $$\lim_{x \to 0^-}\left(x - \frac{2}{x}\right) = \infty$$ More at x→0 from the left $$\lim_{x \to 0^+}\left(x - \frac{2}{x}\right) = -\infty$$ More at x→0 from the right $$\lim_{x \to 1^-}\left(x - \frac{2}{x}\right) = -1$$ More at x→1 from the left $$\lim_{x \to 1^+}\left(x - \frac{2}{x}\right) = -1$$ More at x→1 from the right $$\lim_{x \to -\infty}\left(x - \frac{2}{x}\right) = -\infty$$ More at x→-oo