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

$16x^2-7x+1$

$\frac{1}{\tan x+\tan y}=\frac{\cos x\cos4}{\sin\left(x+y\right)}$

$\left(25\:-\:5y\right)\left(4x^2\:+\:10xy\:+\:25y^2\right)$

$\frac{a^{12}-b^{12}}{a^3+a^2}$

$\frac{dr}{dx}-r\tan\left(x\right)=\sec\left(x\right)$

$y-\left(-3y\right)$