解析√72-√18-3√2/2=6√2-3√2-3√2/2=3√2-3√2/2=3√2/2希望对你有帮助学习进步O(∩_∩)O谢谢
√72+√18-3√2/2=6√2+3√2-3√2/2=6√2+3√2/2=15√2/2