$6r-3r-r$

$-7x+6\le\frac{1}{2}x-13$

$\int t^2\cdot\cos\left(n\:wo\:t\right)dt$

$\frac{4a^2+9b^2}{10a^2-15ab}$

$-3a+4b-6a+81b-114b+81a-a-b$

$\lim_{x\to infinity}\left(e^{\ln\left(x\right)^{\frac{1}{x}}}\right)$

$\lim_{x\to\infty}\left(\frac{12x-4x^2}{x^3-3x^2+4x}\right)$