$\frac{1}{25-sin^2x}$

$\left(4x-x^3\right)^4$

$\frac{x}{-5}\le-8$

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

$\frac{\sin\left(u\right)}{\cos\left(u\right)-\sin\left(u\right)}+\frac{\sin\left(u\right)}{\cos\left(u\right)+\sin\left(u\right)}$

$\left(-5\right)\cdot3+2\cdot\left(-5\right)$

$\frac{x^4}{16}+\frac{1}{2}+\frac{1}{x^4}$