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问题 解答题

正比例函数y=kx与一次函数y=x+b的图象都经过点（1，-3）．

（1）求出这两个函数的表达式；

（2）求两函数图象的交点坐标，并写出一个方程组，使这个方程组的解为以上两个函数图象的交点坐标．

答案

（1）∵y=kx与y=x+b都经过点（1，-3），

∴k=-3，1+b=-3，

解得b=-4，

所以，两个函数的表达式分别为y=-3x，y=x-4；

（2）根据一次函数与二元一次方程组的关系，两函数图象的交点为（1，-3），

方程组

y=-3x
y=x-4
的解为两个函数图象的交点坐标．

阅读理解

阅读理解。

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pink pillow? It's my pillow. I like it very much. The dresser is beside (在……旁边) the bed. It's brown.

And a clock is on the dresser. It's pink and purple. Oh, this is my desk. It's blue. There is a computer on

the desk. I like to use the computer very much. I often use it to do my homework. My books are under

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1. Where is the dresser?

A. Next to (靠近) the bed.

B. Behind the bed.

C. Near the desk.

2. Is the clock on the dresser?

A. No, it isn't.

B. Yes, it is.

C. I don't know.

3. What color is the desk?

A. Green.

B. Red.

C. Blue.

4. Where are the books?

A. Under the desk.

B. Behind the desk.

C. Near the desk.

5. Is there (有) a baseball in the room?

A. No, there isn't.

B. Yes, there is.

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单项选择题

紫外线灭菌最适宜的波长为（）。

A.200mm

B.540nm

C.254nm

D.380nm
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