7) $y = \sqrt{x}(2x - 4)$
$y' = (\sqrt{x})'(2x - 4) + (\sqrt{x})(2x - 4)' = \frac{1}{2\sqrt{x}}(2x - 4) + \sqrt{x}(2) = \frac{2x - 4}{2\sqrt{x}} + 2\sqrt{x} = \frac{x - 2}{\sqrt{x}} + 2\sqrt{x} = \frac{x - 2 + 2x}{\sqrt{x}} = \frac{3x - 2}{\sqrt{x}}$
Ответ: $y' = \frac{3x - 2}{\sqrt{x}}$