$+\left(+8\right)-\left(-2\right)+\left(-5\right)-\left(-6\right)+\left(-9\right)-\left(+5\right)$

$\frac{5}{6}\cdot\left(3-x\right)-\frac{1}{2}\cdot\left(x-4\right)\ge\frac{1}{3}\cdot\left(2x-3\right)-x$

$\frac{y'}{y}=\frac{x+1}{x^20121}$

$x+7<8$

$\left(-120\right)-\left(160\right)-\left(-100\right)+\left(-60\right)+\left(130\right)$

$\frac{5x^7y^9z}{15x^5y^{10}}$

$\lim_{x\to\infty}sin\left(\frac{11}{x}\right)$