$\frac{1+sin\left(-x\right)}{1+csc\left(-x\right)}$

$\left(-9a^2b^5c\right)\left(3a^3b^2c^4\right)$

$\lim_{x\to\pi^1}\left(\frac{\sin^2\left(x\right)}{x-\pi}\right)$

$5y-2\left(y-3x^2\right)+2\left(7x^2-y\right)$

$\frac{d^2}{dx^2}\left(9x^2\ln\left(2x\right)\right)$

$x^2-7x-18=0$

$x^2+\left(x+12\right)^2=\left(x+5\right)^2$