$\sin\left(2x\right)\tan\left(x\right)-1$

$\lim\:_{x\to\:\:1}\left(\frac{x^2+x-2}{x-1}\right)$

$\left(4m^{2}-9n^{2}\right)^{2}-3m^{2}\left(4m^{2}-9n^{2}\right)$

$\left(x+3a\right)^7$

$\lim_{x\to0}\left(\frac{xcos\left(x\right)-2sin\left(x\right)}{x^3}\right)$

$3x^{2}-39x-42$

$\frac{\left(x^4-2x+8\right)}{\left(x^2+x\right)}$