$x^2+18x=63$

$\int_{-2}^{-1}\frac{\left(3x-2\right)}{x^2+4x+5}dx$

$\lim_{w\to0}\:w^2\left(2w^6-3w^4\right)^{-1}$

$\left(x+3\right)^2-\left(x-6\right)^2$

$3x^2-34x+75$

$\sin\left(\frac{4\pi}{21}\right)\cos\left(\frac{\pi}{21}\right)+\cos\left(\frac{4\pi}{21}\right)\sin\left(\frac{\pi}{7}\right)$

$\lim_{x\to-1}\pi$