a) \( \lim{ \left( \frac{n+4}{n-5} \right)^n } = ? \)
b) \( \lim{ \left( \frac{2n+3}{2n-5} \right)^n } = ? \)
c) \( \lim{ \left( \frac{2n+3}{3n+4} \right)^n } = ? \)
d) \( \lim{ \left( \frac{n^2+3n}{n^2+4n} \right)^{4n-7} } = ? \)
e) \( \lim{ \left( \frac{3n^2+2n^3}{5n^2+2n^3} \right)^{6n+4} } = ? \)