$3x^2-9x>0$

$\frac{4\left(3+4\right)}{-5+3\left(1\right)}$

$15a+13b+6a+19b$

$4x-x-8x-2x-8x-2x$

$\left(-19\right)-\left(-15\right)-\left(-11\right)$

$3\log\left(x\right)+2\log\left(y\right)-\log\left(w\right)-4\log\left(z\right)$

$\lim_{w\to39}\left(\frac{\cos\left(wx\right)-\cos\left(39x\right)}{1521-w^2}\right)$