$5^2.\:5^{-1}$

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

$9r^7-6r^5-3r^3$

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

$\left[25+3\cdot\left(5\cdot3\right)\right]\cdot\left[\frac{\left(6+8\right)}{\left(\frac{6}{3}\right)}\right]$

$\left(654\right)+432$

$\frac{x^5}{16-x^2}$