题目

The rising costs of health care have become a problem for many countries in the world. To deal with this problem, it is recommended that a big part of the government's health budget be used for health education and disease prevention instead of treatment. Actually, many kinds of diseases are preventable in many ways and preventing a disease is usually much cheaper than treating it. For example, people could avoid catching a cold if they dressed warmly when the weather starts getting cold. But many people get sick because they fail to do so, and have to spend money seeing a doctor        已知函数,则满足不等式的x的范围是__▲___。