$\left(2t+5x\right)\left(2t-5x\right)$

$y^3\cdot\frac{d^2y}{dx^2}+\frac{16}{9}=0$

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

$2x\cdot5x+4x\cdot3x$

$\sqrt{a^2+\frac{1}{a^2}+4\left(a+\frac{1}{6}\right)+6}$

$3y^2+9y^2-2y^2$

$\left(\frac{6}{5}m^3k\:+\:\frac{8}{3}m\right)\left(\frac{6}{5}m^3k\:-\:\frac{8}{3}m\right)$