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

$2\cdot3\left(5-4\right)-\left(4+3\cdot2-2\right)$

$\int_0^1\left(\frac{e^x}{81-e^{2x}}\right)dx$

$\left[\left(-8\right):\left(-2\right)-6:\left(2-5\right)\right]\::\:\left[10:\left(-2\right)-3:\left(1-2\right)\right]$

$\int\left(\frac{5x^2}{e^{5x}}\right)dx$

$\frac{dy}{dx}=\frac{c\left(2\right)}{3x^2+1}$

$\int\:\frac{5}{x^2+1}dx$