$300-\left(5-2\right)-\left(9-3\right)-\left(5-4\right)$

$4x^2+2xy+3y=9$

$\int\frac{\left(x+1\right)}{\left(x^2+2x+2\right)}dx$

$\frac{\left(x^2+5x\right)}{x^2+5}$

$\int3a^{3}dx$

$\left(8-12\right)-\left(2-5\right)$

$-\frac{\cos^2\left(x\right)}{\sin\left(x\right)}=2\sin\left(x\right)-\csc\left(x\right)$