2√12+√27
=4√3+3√3
=7√3
√18-√2分之9
=3√2-3/2√2
=3/2√2
3分之2√9x+6√4分之x
=2√x+3√x
=5√x
a的平方√8a+3a√50a的3次方
=2a²√2a+15a²√2a
=17a²√2a 谢谢啦