find the limits :$$\lim_{ x \to \infty}\frac{\sqrt{x+1}+\sqrt{x+2}-\sqrt{4x+12}}{\sqrt{x}+\sqrt{x+2}-\sqrt{4x+12}}$$
WolframAlpha gives me: $$\lim_{ x \to \infty }\frac{\sqrt{x+1}+\sqrt{x+2}-\sqrt{4x+12}}{\sqrt{x}+\sqrt{x+2}-\sqrt{4x+12}}=3/4$$
What is a simple way for the limits?