$$\frac{dy}{dx}\left(xy+4x^2+y^2=6\right)$$

$$\int\left(1-t\right)e^{4t-2t^2}dt$$

$$2x^2+12xy+18y^2$$

$$\lim_{v\to\infty}\left(\frac{-x^3+6x^2-8x+1}{3x^2-7x^3+2x-3}\right)x^2$$

$$\frac{3}{10}b^4\::\:b$$

$$y'=2y-4$$