2.1.36 Calculation of limits
condition: Find the specified limits. a) \( \lim _{x \rightarrow 5} \frac{x^{2}-2 x-15}{11 x^{2}-61 x+30} \) b) \( \lim _{x \rightarrow \infty} \frac{7-8 x-x^{2}}{3 x^{2}+x+9} \).
Calculation of various limits, using L'Hopital's rule, remarkable limits, power series, equivalent values of various other methods.