$\frac{\left(x+1\right)\left(x-10\right)}{\left(x-1\right)\left(x+10\right)}$

$9y^5z+17y^3-4xyz$

$x^{2}-10x+24-\frac{3}{x-6}+1$

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

$4+36:9.50:\left|12+\left(17-4\right)\right|$

$\frac{\left(1+\cos\left(x\right)\right)\left(1-\cos\left(x\right)\right)}{\sin^2\left(x\right)}=\frac{1+\cos\left(x\right)}{1-\cos\left(x\right)}$

$\ln\left(\frac{\cos x}{\cos x-1}\right)$