$t^2-2t\cdot5z+\left(5z\right)^2$

$\frac{dy}{dx}=8x^4\left(7+y^2\right)^{\frac{3}{2}}$

$3^{5.49}$

$3x+9-x=-1$

$\frac{5+y}{5}+\frac{5+z}{6}$

$\frac{\sec\left(u\right)+1}{\sec\left(u\right)-1}=\frac{1+\cos\left(u\right)}{1-\cos\left(u\right)}$

$1-2\sen^{2}x=\frac{1}{1+\tan^{2}x}$