$\left(4b^3\right)\left(5b^5\right)$

$\lim_{x\to\infty}\left(x\left(-e^{-x}\right)\right)$

$\left(\frac{3}{2}d+\frac{4}{3}c\right)^3$

$3\left(x^2+2\right)^{-\frac{1}{2}}xe^{\sqrt{x^2+2}}$

$\frac{df}{dx}\cos x^2y\left(6x\right)-\cos y^3\left(6x^2\right)$

$\frac{dy}{dx}=\left(4x+7\right)\left(5y+4\right)$

$-2\left(7d-1\right)+3d$