$
\eqalign{
& y = \sqrt {3 + 4x - x^2 } \cr
& y' = \frac{1}
{{2\sqrt {3 + 4x - x^2 } }} \cdot \left( {4 - 2x} \right) \cr
& y' = \frac{{2 - x}}
{{\sqrt {3 + 4x - x^2 } }} \cr
& y' = \frac{{2 - x}}
{{\sqrt {3 + 4x - x^2 } }} \cr
& y' = \frac{{2 - x}}
{y} \cr}
$