$\left(3\cdot3000\right)+\left(5\cdot3\cdot0.01\right)$

$-12\cdot\left(-3+4\right)-5\cdot\left(-6\right)$

$\lim_{x\to0}\left(\frac{\cos\left(6x\right)-1}{x^2}\right)$

$\frac{dy}{dt}=-\frac{1}{40}\left(y-t\right)$

$\frac{1+tan^2\left(a\right)}{csc^2\left(a\right)}+sin^2\left(a\right)+\frac{1}{sec^2\left(a\right)}$

$x^2inx$

$\frac{x}{5}+\frac{2x+1}{3}$