一元二次方程x2+kx-3=0的一个根是x=1,则k的值为( )
A.2
B.-2
C.3
D.-3
把x=1代入x2+kx-3=0中,得
1+k-3=0,
解得k=2,
故选A.
如果“+200元”表示收入200元,那么“-100元”的实际意义是______.
阅读理解。
This is No.12 High School. My friend Dongdong is in this school. Dongdong has long hair, a big nose, a small mouth and big eyes. He is thirteen. He is in Class Two, Grade Seven. He's a good student. He
has two good friends in his school. They are Jim and Jack. They're brothers(兄弟). They are fourteen.
They have small noses, small eyes, but they're very tall(高的). Jim, Jack and Dongdong are in the same
class. Mr. Lee is their(他们的) teacher. They are good friends.
1. Dongdong is in _____.
A. No.2 High School
B. Class 2, Grade 1
C. Class 2, Grade 7
D. Class 2, Grade 8
2. How old is Dongdong? He is _____.
A. fourteen
B. thirteen
C. twelve
D. eleven
3. Mr. Lee is _____.
A. Tiantian's brother
B. Tiantian's teacher
C. Dongdong's teacher
D. Jim's brother
4. Jim is _____.
A. an English boy
B. an English teacher
C. a Chinese boy
D. Sorry, I don't know
5. Who has big eyes?
A. Jim.
B. Dongdong.
C. Tiantian.
D. Jack.