Question

Помогите...........................

Answer 1

$1)\sqrt{81}=\sqrt{9^2}=9\\\\ 2)\sqrt{0,04}=\sqrt{\frac{1}{25} }=\frac{1}{5}=0,2\\\\ 3)\sqrt{0}=0\\\\ 4)-\sqrt{9}=-\sqrt{3^2}=-3$

Answer 2

$\displaystyle\bf\\\sqrt{81} =\sqrt{9^{2} } =\boxed9\\\\\sqrt{0,04}=\sqrt{0,2^{2} } =\boxed{0,2}\\\\\sqrt{0} =\boxed0\\\\-\sqrt{9} =-\sqrt{3^{2} } =\boxed{-3}$