$\left(0.8a^2b+3.8a\right)\left(8ab-9a\right)$

$2-4w+5$

$\lim_{x\to0}\left(\frac{e^{2x}-x-\cos\left(x\right)}{\sin\left(x\right)}\right)$

$6m^2n^2+7m^2n$

$\left(t^2+25\right)\frac{dx}{dt}=\left(x^2+4\right)$

$\frac{d}{dx}\left(y=\frac{7x^5-2x^2}{6x^3+8x}\right)$

$\frac{d}{dx}28$