问题
选择题
已知f(x)=
|
答案
因为在每段定义域对应的解析式上都有可能使得f（x）=3成立，所以将原不等式转化为：
或x+1=3 x≤-1
或x2=3 -1＜x＜2
，从而得x=2x=3 x≥2
．故选D．3
搜题请搜索小程序“爱下问搜题”
已知f(x)=
|
因为在每段定义域对应的解析式上都有可能使得f（x）=3成立，所以将原不等式转化为：
或x+1=3 x≤-1
或x2=3 -1＜x＜2
，从而得x=2x=3 x≥2
．故选D．3
| 完形填空。 | ||||
| Everyone 1 to live in a clean and comfortable environment. If the environment is 2 , it will make us not 3 well. Sometimes we may be terribly ill. At that time we don't want to 4 , we have to stay in bed and rest at 5 . So the environment is very important 6 us. It is germ that makes us ill. There are germs everywhere. They are very small and we can't 7 them with our own eyes. To keep us 8 , we should try our best 9 our environment become cleaner and tidier. This needs us to act 10 . | ||||
|