#### Answer

$2\sqrt {5x}-24\sqrt {x}+4\sqrt {2x}$

#### Work Step by Step

$\sqrt {20x}-6\sqrt {16x}+\sqrt {32x}$
=$\sqrt {4\times5x}-6\sqrt {4^{2}\times x}+\sqrt {2x \times16}$
=$2\sqrt {5x}-(6\times4)\sqrt {x}+4\sqrt {2x}$
=$2\sqrt {5x}-24\sqrt {x}+4\sqrt {2x}$