经市场调查，某种商品的进价为每件6元，专卖商店的每日固定成本_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题填空题

经市场调查，某种商品的进价为每件6元，专卖商店的每日固定成本为150元．当销售价为每件10元时，日均销售量为100件，单价每降低1元，日均销售量增加40个．设单价为x元时的日均毛利润为y元，则y关于x的函数解析式为______．

答案

单价为x元时，日销量是（400-40x）个；每件的利润是：（x-6）元；

则利润y=（x-6）（400-40x+100）-150，即y=-40x²+740x-3150（6≤x≤10）．

故答案为：y=-40x²+740x-3150（6≤x≤10）．

改错题

Dear Xiao Fei,
     I'm glad to receive your e-mail. I'd like to discuss
the problem which you mentioned in it to you.

    It's true that some computer games are real interest-
ing
and they can sometimes make you felt relaxed. However,
it
uses you too much time to do that. You are not a little
boy.
You should learn to control (控制) ourselves. Why not

trying to finish your homework first every day and then

spend a little time surf the Internet? You'll find many
other
thing that are also very interesting, such as visiting cool

websites, learning the latest news but listening to the
music.
    I'm sure you'll become an useful person in the
future.
    Best Wishes!
    Yours.
    Gao Hui

1._____

2._____

3._____

4._____

5._____

6._____

7._____

8._____

9._____

10._____

单项选择题

粉尘中游离二氧化硅含量50%～﹤80%，呼吸性粉尘最高允许浓度为（）mg/m3。

A.1

B.2

C.0