2. Use the quotient rule: $\left(\frac{f(x)}{g(x)}\right)' = \frac{f'(x)g(x) - f(x)g'(x)}{\big[ g(x) \big]^2}$
Imagine: $f(x) = x^2$ and $g(x) = 1+x$
So: $\frac{d}{dx} \left( \frac{x^2}{1+x} \right) = \frac{(x^2)'(1+x) - x^2(1+x)'}{(1+x)^2} = \hdots$