$$\left(2x-7\right)\left(x-7\right)$$

$$3\left(a^2\right)^2-\left(6b^2\right)^2$$

$$\lim_{x\to1}\left(1-2x\right)^{\frac{1}{x}}$$

$$\frac{dy}{dx}\left(y=x\sqrt{x^2+1}\right)$$

$$2x^2+3=7x$$

$$\int_4^{20}\left(\left(-\frac{1}{2}\right)\cdot\left(\left(\frac{x}{5}\right)-4\right)^2+25\right)dx$$

$$\left(\frac{7}{9}a^3-\frac{2}{5}b^2\right)\left(\frac{2}{5}b^2+\frac{7}{9}a^3\right)$$