题目

阅读理解。 A computer company has a special person. He answers all the questions sent to him. The person is a 63- year-old man. He is know for always finding the right answers . On the  Internet ,more people are finding out about this clever man . He does not  look like a computer expert (专家). He has white hair and he is kind and polite .He feels that his age helps him with his work . People have  askesd questions about a lot of things and he  remembers most of them. He tries to return the answers within 24 hours on the Internet. The questionts are very different each day 解方程 2.5x＋3.7=11.5         x=(　　)