$$\left(5a-8b\right)\left(5a+8b\right)$$

$$\left(6x^2+x^3\right)$$

$$\int\frac{1}{\left(7t+8\right)^{1.4}}dt$$

$$\:a\left(x+4\right)+b\left(x-3\right)=4x+9$$

$$x^2-4x+10$$

$$\sqrt{121x^4y^2}+3x^2y$$

$$\lim_{x\to-1}\left(\frac{4x^4+5x^3+5x+6}{x+1}\right)$$