$\cos\left(3x\right)\sec\left(x\right)-2\cos\left(3x\right)=0$

$\int\frac{x^2}{\sqrt{\left(x^2+64x\right)}3}dx$

$\int\frac{1}{2x^2+4x}dx$

$-3\sqrt{x^2}$

$\left(x^2y^3z^4\right)^4\left(x^6y^5\right)^2$

$\int\frac{10x}{\left(6-5x^2\right)^4}dx$

$\frac{-9^3-9x^2-x}{x^2+9}$