$\frac{14a^{-4}}{20bc^{-1}}$

$\frac{\sec\left(x\right)^2}{1+\frac{\cos\left(x\right)^2}{\sin\left(x\right)^2}}$

$\int_0^{\infty}\left(\frac{90}{\left(3x+1\right)^4}\right)dx$

$\left(-3-a\right)^2$

$x^4+x-18$

$3tan-6=1+\tan\left(x\right)$

$\frac{x}{x-y}+\frac{x}{x+y}$