$$\left(7x^2+5bx^3\right)\left(5bx^3-7x^2\right)$$

$$\int_1^{\infty}\left(3-\frac{sen\left(x\right)}{x}\right)dx$$

$$\lim_{x\to6}\left(\frac{x^2-6x+36}{x-6}\right)$$

$$\left(70-y\right)^2$$

$$\frac{dy}{dx}+\frac{2y}{x}=e^x$$

$$\left(1-sinx\right)\left(1+sinx\right)=1-sin^2x$$

$$\left(-5m^2n\right)\cdot\left(-4mn\right)$$