$\int\frac{\left(x^2+6\right)}{x^3+3x}dx$

$\left(12-13\right)-\left[1-\left(2-6\right)\right]$

$15mn^4+3m^4n^4-123m^3n^2x$

$2-3+2-7$

$\left(\sin\left(x\right)-\csc\left(x\right)\right)\left(3\sin^2\left(x\right)+3\csc^2\left(x\right)+3\right)$

$\int x^4\left(4+x^5\right)^3dx$

$\int_{-\infty}^1\frac{1}{x^2-4x+8}dx$