$$\frac{1+\sin\left(u\right)}{\cos\left(u\right)}+\frac{\cos\left(u\right)}{1+\sin\left(u\right)}=2\sec\left(u\right)$$

$$\lim_{x\to\pi}\left(x+\pi\right)\cot\left(x\right)$$

$$25x^2-5x+10$$

$$\frac{x^7}{7}+\frac{x^6}{2}+\frac{x^5}{2}-\frac{x^3}{6}+\frac{x}{42}+\left(x+1\right)^6$$

$$5\left(1.5\right)^3$$

$$\left(5\:\cdot\:6\right)\:\cdot\:\left(1\cdot\:6\right)$$

$$x\left(a-5\right)+3\left(a-5\right)$$