$$2x\left(x+1\right)-x\left(x-1\right)$$

$$\lim_{x\to0}\left(\frac{2^x-1}{2^{x-1}}\right)$$

$$n\:-2\:+n\:+1$$

$$x-y^3=3$$

$$18x-10<62$$

$$w^2\:x\:w^{-5}\:x\:z^7$$

$$\left(\frac{4}{3}a+\frac{1}{2}b\right)-\left(\frac{3}{2}a+\frac{1}{3}b\right)$$