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

$\lim_{x\to1}\left(x-\ln\left(x^2+1\right)\right)$

$3x-1=x-11$

$\lim_{x\to\infty}\left(\frac{ln\left(n\right)}{ln\:\left(n+1\right)}\right)$

$b^4c^2\:-\:16b^2cd+64d^2$

$ab^2c^2\cdot a^4bc^3$

$\left(\sqrt{3-x}\right)\left(x+\sqrt{3}\right)$