$$\left(\frac{1}{3}+x^3\right)^3$$

$$1a$$

$$-xy^{4}-y^{4}x^{2}=80x^{2}-3y^{4}x^{5}$$

$$17+\left(-9+13-16\right)-\left(6-18\right)$$

$$\frac{dy}{dx}\:+\:y=e^x$$

$$\left(k+2\right)\left(k+5\right)$$

$$\frac{\cot\left(x\right)}{\left(1-\sin\left(x\right)\right)}=\frac{1+\sin\left(x\right)}{\cot\left(x\right)}$$