$+2+1-4-3+6$

$\left(3x-3\right)\left(-3x+3\right)$

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

$\lim_{x\to infinity}\left(\frac{xe^{-2x}}{3e^{2x}-100}\right)$

$-15x^9y^5+9x^8y^4z-12x^5yz^{4\left\{\right\}}$

$-10\left(-7\:-\:10r\right)$

$4\left(-2^3-3.-2\right)+\left(-2^2+4.-2\right)-6\left(-2^3+-2^2\right)$