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