$\left(-1\right)\:x\:\left(2\right)\:x\:\left(-1\right)\:x\:\left(-2\right)\:x\:\left(-1\right)\:$

$\frac{x^2+12x+12}{x+4}$

$2cos2x+2cosx=0$

$\frac{-12x-8x^2}{4x^2}$

$\left(0.205+1.72x+0.851y\right)+\left(-0.509+0.953x-1.72y\right)$

$9+\frac{9}{3}$

$\tan\left(a\right)\sec\left(a\right)+\frac{1}{1+\sin\left(a\right)}=\sec^2\left(a\right)$