$\frac{x^2+7x-1}{x-1}$

$133\:,\:y\:=\:19$

$\frac{1}{cos^24x}$

$\frac{sin^2\left(a\right)\:+2cos^2\left(a\right)}{\sin\left(a\right)\cdot\cos\left(a\right)}=\tan\left(a\right)+2\cot\left(a\right)$

$-a=1$

$16x+15x^2-15$

$\left(-cos\:\left(y\right)\right)dx\:+\:\left(xsen\left(y\right)-1\right)dy=0$