$x^4-3x^3+5x^2-9x+6$

$\lim_{x\to0}\frac{\left(x\cdot4^x\right)}{4^x-1}$

$15m^5n^2+35m^3n^3+45m^2n^5$

$2\left(-3-2m\right)\left(-5+8n\right);\:m=2;\:n=4$

$\lim\:_{x\to\:\:-\infty\:\:}\frac{\left(\arctan\:\left(x\right)sen\left(\frac{1}{x}\right)\right)}{e^{\frac{1}{x}}-1}$

$6-5\left(1-2\cdot3+4\cdot2\right)$

$\frac{dy}{dx}=-32-0.005y$