根号4a+根号a-根号9a
问题描述：
根号4a+根号a-根号9a
答
根号4a+根号a-根号9a
=2根号a+根号a-3根号a
=0
答
√4a+√a-√9a=2√a+√a-3√a
=(2+1-3)√a
=0