$-6\:-\:\left(5\:-\:10\right)$

$25r^4-144$

$4+\left(-7+\left(3+2\right)-\left(-2\right)+\left(-3\right)-\left(+8-8\right)\right)+\left(-10\right)+10-3$

$secx=-4$

$\:f\left(x\right)\:\:=\:\:3\:\cdot\:x^2\:-\:2\:y\:g\left(x\right)\:\:=\:2\cdot\:x\:-\:1\:\left(\:\frac{f}{g}\right)\:\left(4\right)\:$

$+1-8+6-4+9-5-6-4+7+1$

$\frac{dy}{dx}\left(y=\frac{\left(-2x^3+e^{7x}\right)}{7x}\right)$