$\left(-3\right)^2\cdot\left(-3\right)^2$

$\cos\left(u\right)=-\cos\left(2u\right)$

$\log\left(x^2\right)-\frac{1}{2}\log\left(y\right)$

$\frac{49m^3n^4}{63m^3n}$

$\left(\frac{9}{20}d^5\right)\left(2d^{-2}\right)\left(\frac{4}{3}d^9\right)$

$x^4-x^3+\frac{x^2}{4}$

$9\:-\:5x\:+\:3$