$$\int\left(x\right)e^{\frac{x}{a}}dx$$

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

$$\left(-3xy^3\right)^2$$

$$x^2+10x=36$$

$$\left(-1\right)\cdot\left(-6\right)$$

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

$$85\cdot39$$