$\frac{x+1}{4x}=\frac{x-1}{3x}$

$-3t\:=6$

$\frac{d}{dx}\left(y=\sqrt{x^2+38}\right)$

$\frac{9\sec^2\left(x\right)-9}{\sec\left(x\right)-1}$

$9+a^2=4a^2$

$\left(\frac{2}{3}\right)^0x\left(\frac{2}{3}\right)^1x\left(\frac{2}{3}\right)^2$

$\lim_{x\to1}\left(\frac{sin\left(\pi x\right)}{cos\left(\pi x\right)+x}\right)$