$\sqrt{18}=\sqrt{x^2}$

$9-25^2$

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

$\frac{x^{n+1}\left(1+3x+x^2-x^3\right)}{x-1}$

$\frac{4x-3}{x^4+2x^3+3x^2}$

$1-2\cdot\sin\left(x\right)^2-\sin\left(x\right)=0$

$\left\{12\:-\left[45:\left(-9\right)+\left(-6\right).\left(-1\right)-\left(-5\right)+3\right]\right\}.\left(-1000\right)$