1, \(lim\frac{3}{n-2}=lim\frac{n\frac{3}{n}}{n\left(1-\frac{2}{n}\right)}=0\)
2, \(lim\frac{n-1}{n-2}=lim\frac{n\left(1-\frac{1}{n}\right)}{n\left(1-\frac{2}{n}\right)}=1\)
3, \(lim\frac{7n^2-3}{n^2-2}=lim\frac{n^2\left(7-\frac{3}{n^2}\right)}{n^2\left(1-\frac{2}{n^2}\right)}=7\)