$$\frac{9^2}{4}-ab+b^2$$

$$\lim_{x\to8}\left(\frac{4x^3}{e^x}\right)$$

$$\frac{d}{dx}\frac{x^2-11x}{4}$$

$$\int\:x\:e^{2x^2}dx$$

$$\int10c^{-7x}dx$$

$$\int\frac{x-3}{\left(x^2+4\right)\left(x-1\right)}dx$$