√50-﹙1/√5-√45+2√20

问题描述:

√50-﹙1/√5-√45+2√20

后面少个括号吧
√50-﹙1/√5-√45+2√20)
=5√2-(√5/5-3√5+4√5)
=5√2-(6/5)√5