$\frac{x^3-6}{3x^2}$

$\left(7e+9\right)\left(7e-9\right)^2$

$3\left(x^2+3x+1\right)+5\left(x^2+2x+2\right)$

$2\cos\left(x\right)\cos\left(y\right)=cos\left(x+y\right)+\cos\left(x-y\right)$

$\left(x+1\right)dy=\left(2x+\left(x+a\right)^4\right)dx$

$\left(a^2x+by^2\right)^5$

$5x^2-20$