Tính các giới hạn sau:
a) \(\lim \frac{{2{n^2} + 6n + 1}}{{8{n^2} + 5}}\)
b) \(\lim \frac{{4{n^2} - 3n + 1}}{{ - 3{n^3} + 5{n^2} - 2}}\);
c) \(\lim \frac{{\sqrt {4{n^2} - n + 3} }}{{8n - 5}}\);
d) \(\lim \left( {4 - \frac{{{2^{n + 1}}}}{{{3^n}}}} \right)\)
e) \(\lim \frac{{{{4.5}^n} + {2^{n + 2}}}}{{{{6.5}^n}}}\)
g) \(\lim \frac{{2 + \frac{4}{{{n^3}}}}}{{{6^n}}}\).