$8n-\left(5n+8\right)=4$

$\left(5-\:6\right).3$

$\tan\left(x\right)\cdot\sec\left(x\right)\tan\left(x\right)$

$-4\left(-11+4n\right)-3\left(-n+9\right)$

$2\ln\left(y\right)=3\ln\left(x-1\right)+x$

$\int\frac{x^3+7}{x^3-9x}dx$

$\int\left(\frac{x^2}{\left(2-x^3\right)^4}\right)dx$