题目

  Chinese social media apps have struggled to win over users beyond their home. TikTok is changing that. In the space of just two years, the app has attracted more than half a billion users — around 40% of them outside China --who share short videos of themselves singing, cooking, dancing or just being silly. Created by the Beijing-based Internet technology company Byte Dance, TikTok has gained an international edge over China's influential social media platforms, such as Tencent's WeChat, Sina Weibo (WB) and Youku of Alibaba (BABA). What makes Byte Dance better is its right directi17．（x2-x-2）6的展开式中x2的系数等于（　　）A．-48B．48C．234D．432