$\left(4y+1\right)=x\cdot y\frac{dy}{dx}$

$\int\frac{\sqrt{y^2-4}}{y}dy$

$4x+v-2x-x-v$

$f\left(x\right)=\left(1+9x^2\right)\left(x-x^2\right)$

$\frac{8x^3+1}{4x+1}$

$-14+2\left(-9+6\cdot3\right)$

$\lim_{x\to\infty}\left(\frac{7x^2+5x-x^5+7x^3}{4x^2-7x+x^4+5}\right)$