题目

New York City schoolchildren can’t use cellphones at school because of Mayor Michael R. Bloomberg’s ban on cellphones in schools. Many parents are opposed to Mayor Michael R. Bloomberg’s ban on cellphones in schools by e-mail messages.     There was a 13-year-old student who was shot with a gun after school, unable to call his mother for help. There was a high school student robbed three times last year, twice in her school building. There was a girl who got a piece of glass placed in her eye during school and was saved from a possible cornea transplant (角膜移植) only bec分式方程xx-5=x-4x+6的解是x= ．