$$6+x+4$$

$$6x^3\left(x^2-3x^4\right)$$

$$x^4-x-2$$

$$\frac{d}{dx}\left(\tan\left(xy\right)=\frac{x}{y}\right)$$

$$-2\ln\left(x+1\right)-3=7$$

$$\cos\left(x\right)uf-ux=0$$

$$\log\left(x\right)+\log\left(y\right)=0$$