$\int_0^{\frac{\pi}{2}}\left(\sqrt{16-x^2}\right)dx$

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

$\left(1+\cot^2x\right)\tan x=\left(\csc^2x\right)\tan x$

$6\left(x+3\right)+8\left(7-x\right)$

$6x\cdot9$

$\left(1-\left(.75\right)xy\right)^2$

$\left(t-1\right)\left(t^2-3\right)\le0$