$$\left(\left(8\right)^2\right)^{-2}\:+\left(\left(6+3\right)^3\right)^{-5}$$

$$\tan\left(\theta\:\right)\cot\left(\theta\:\right)=1$$

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

$$\sqrt{3xy^2}$$

$$\left(8\right).\left(-6\right):\left(-12\right)$$

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

$$\left(13xz\right)\:\left(12x^2y^3z\:+14xy\right)$$