$\sqrt{a}+\sqrt{b}=15$

$40x^4\cdot6x^2$

$\frac{\left(x^4+0x^3+0x^2+0x-2\right)}{x+3}$

$\lim_{x\to\infty}\left(\frac{x^3}{2\left(1+x\right)^2}\right)$

$\left(\frac{x}{2}\left(-3\right)\right)$

$\left(4+x\right)^2-\frac{16}{\left(4+x\right)+4}$

$\frac{dy}{dx}=\ln\left(ax+b\right)$