Question

Помогите решить пределы)

Answer 1

$\large \\ \lim_{x\to1}{3x^2+5x-8\over11(1-x)}=\begin{vmatrix} 3x^2+5x-8=0\\ D=25+96=121\\ 3x^2+5x-8=(x-1)(3x+8) \end{vmatrix}=\lim_{x\to1}{(x-1)(3x+8)\over11(1-x)}=\lim_{x\to1}{(x-1)(3x+8)\over-11(x-1)}=-{1\over11}\lim_{x\to1}(3x+8)=-{1\over11}\cdot11=-1\\\\ \lim_{x\to\infty}{5x^2+4x+2\over x-2x^2+1}=\lim_{x\to\infty}{x^2(5+{4\over x}+{2\over x^2})\over x^2({1\over x}-2+{1\over x^2})}=-\lim_{x\to\infty}{5\over2}=-2,5$