$$2x+4y=28$$

$$\frac{dy}{dx}\left(x^2y+x^2+y^2=0\right)$$

$$-40+15+10-80$$

$$\lim_{x\to0}\left(-3x^3-7x^3+8\right)$$

$$\lim_{x\to\infty}\left(\frac{\left(x^3\cdot e^{-8\cdot x}\right)}{-8}\right)$$

$$2\cdot6^4$$

$$f\left(x\right)=x^2+x\:\:\:\:g\left(x\right)=-2x^2-1$$