$5x^3-3x^2-6x-4.-8x^3+2x^2-3.7x^2-9x+1$

$\sqrt{2-2x}-\frac{x-1}{\sqrt{2-2x}}$

$9\sin\left(18x\right)+11=2$

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

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

$\lim_{x\to0}\cos\left(\pi x+\frac{\pi}{2}\right)\sec\left(\frac{\pi}{2+x}\right)$

$\cos x+2\sin2y=1$