$2\cdot3^x-5\cdot3^{x-2}=39$

$\left(3x^3y^4\right)^3.-2yx^3$

$\sqrt[5]{\frac{5y^2x^7}{27x^2}}$

$\frac{2}{3}x^{3}-\sqrt{18}\right)\left(\frac{2}{3}x^{3}+\sqrt{72}\right)$

$\frac{xe^{3x}}{\left(6x+2\right)^2}$

$\frac{dy}{dx}\left(arctan\left(\frac{x}{2}\right)+arctan\left(\frac{2}{x}\right)\right)$

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