## Calculus (3rd Edition)

$$1$$
Since the function $\lim\limits_{(x,y) \to (2,5)}f(x,y)=3$ and $\lim\limits_{(x,y) \to (2,5)}g(x,y)=7$, then we have $$\lim\limits_{(x,y) \to (2,5)}(g(x,y)-2f(x,y))=\lim\limits_{(x,y) \to (2,5)}g(x,y)-2\lim\limits_{(x,y) \to (2,5)}f(x,y)\\=7-2(3)=7-6=1.$$