$\left(6-2\left(8\right)\right)$

$10m+15n+20g$

$\frac{-6x^3+2x^2+9x+3}{-2x^2+5}$

$\left(\frac{x^2}{4}+\frac{xy\sin\left(\frac{y}{x}\right)}{4}\right)\frac{dy}{dx}=\frac{y^2\sin\left(\frac{y}{x}\right)}{4}$

$\left(+2\right)\cdot\left(-5\right)+\left(-4\right)\cdot\left(-7\right)$

$\frac{x^2+y^2}{y}-x$

$x^2-2x+35$