问题
解答题
m为何整数时，关于x的方程3x2+6x+m=0有两个负实根？
答案
设方程3x2+6x+m=0的两个负实根分别为x1、x2，
则有
，即△=36-4•3•m≥0 x1•x2=
＞0m 3
；m≤3 m＞0
∴0＜m≤3；（2分）
∴m=1，2，3．（1分）
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m为何整数时，关于x的方程3x2+6x+m=0有两个负实根？
设方程3x2+6x+m=0的两个负实根分别为x1、x2，
则有
，即△=36-4•3•m≥0 x1•x2=
＞0m 3
；m≤3 m＞0
∴0＜m≤3；（2分）
∴m=1，2，3．（1分）
根据短文内容，从A、B、C、D四个选项中选择一个最佳答案，将字母标号写在答题纸的相应位置上.（共10分，每小题1分） Children like to copy what they hear. They copy their parents, their friends and even the TV. This teaches them how to _1_ the language. Copying is also a good way for students to learn a second language. When you _2_ foreigners speak English, repeat what they say as well as you can. Children don't practice grammar,, but use the language to 3_ things that they are interested in. They don't _4 their vocabulary or poor grammar. They find ways to express themselves, and they do it successfully. Students of English schools also pay attention to communication (交流). Look for _5_ to talk with people in English. If you can't find a _6 to talk to, talk with other students in English _7. Start an English discussion group and talk about music, movies or anything that 8 you. Don't worry about _9, what you want is to learn how to communicate easily. Remember that you can communicate successfully even with _10_small vocabulary.
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