$\frac{3n}{\frac{2n^2+6}{\frac{3n}{2n^2}}}$

$\lim_{x\to\infty}\left(\frac{x}{e^x+16x}\right)$

$\frac{18x^2+6x}{\sqrt[4]{2x^3+x^2+1}}$

$\lim_{x\to1}\left(4-4x\right)$

$\lim_{x\to\infty}\left(\sqrt{x^2+ax}\right)-\left(\sqrt{x^2+bx}\right)$

$\left(-42\right).29$

$-26\:.\:-19$