根号b/5除以根号b/20a的平方*根号b/a
问题描述：
根号b/5除以根号b/20a的平方*根号b/a
答
√(b/5)÷√(b/20a²)*√(b/a)
=√[(b/5)*(20a²/b)*(b/a)]
=√(4ab)
=2√ab