Multiply. \[ \sqrt{5}(\sqrt{20}-3) \]

To simplify the expression \( \sqrt{5}(\sqrt{20}-3) \), we can first simplify \( \sqrt{20} \): \[ \sqrt{20} = \sqrt{4 \cdot 5} = \sqrt{4} \cdot \sqrt{5} = 2\sqrt{5} \] Now substituting this back into the expression: \[ \sqrt{5}(2\sqrt{5} - 3) = \sqrt{5} \cdot 2\sqrt{5} - \sqrt{5} \cdot 3 \] Calculating \( \sqrt{5} \cdot 2\sqrt{5} \): \[ \sqrt{5} \cdot 2\sqrt{5} = 2(\sqrt{5} \cdot \sqrt{5}) = 2 \cdot 5 = 10 \] Now calculating \( \sqrt{5} \cdot 3 \): \[ \sqrt{5} \cdot 3 = 3\sqrt{5} \] Putting it all together: \[ 10 - 3\sqrt{5} \] Thus, the final result is: \[ \boxed{10 - 3\sqrt{5}} \]