$\lim_{x\to\infty}\left(\frac{1}{\sqrt{x}-4}-\frac{8}{x-16}\right)$

$2x^2+9x+10=0$

$\lim_{x\to0}\left(\frac{cosx-cos3x}{sinx^2}\right)$

$\left(-3\right)^2\left(-3\right)^2\left(-3\right)$

$x ^ { 3 } + 5 x - 5 x + 25$

$-[62+43\right)-\left(46-26\right)-\left(34$

$\lim_{x\to\infty}\left(\frac{x^2+10x+25}{625-x^4}\right)$