Answer:
Explanation:
Rewriting 400 as 20².
Cancelling the square root and the power.
<em>√400 = 20</em>
<em>√400 =</em>
<em>= √4×100</em>
<em>= √2²×10²</em>
<em>= √(2×10)²</em>
<em>= √20²</em>
<em>= 20</em>
