<s>[INST] What is $ \lim_{(x,y)\to(2,2)}\frac{x^4-y^4}{x^2 - y^2} $? I have limit:
$$
\lim_{(x,y)\to(2,2)}\frac{x^4-y^4}{x^2 - y^2}
$$
Why is the result $8$ ?
 [/INST] $$\lim_{x,y\to{2,2}}\frac{x^4-y^4}{x^2-y^2}$$ $$= \lim_{x,y\to{2,2}}\frac{(x^2+y^2)(x^2-y^2)}{x^2-y^2}$$
$$\lim_{x,y\to{2,2}} x^2+y^2 =...$$
</s>