题干

在2014年巴西世界杯足球赛前夕,某体育用品店购进一批单价为40元的球服,如果按单价60元销售,那么一个月内可售出240套.根据销售经验,提高销售单价会导致销售量的减少,即销售单价每提高5元,销售量相应减少20套.设销售单价为x(x≥60)元,销售量为y套.
(1)求出y与x的函数关系式.
(2)当销售单价为多少元时,月销售额为14000元;
(3)当销售单价为多少元时,才能在一个月内获得最大利润?最大利润是多少?
[参考公式:抛物线y=ax2+bx+c(a≠0)的顶点坐标是(-
b
2
a
,
4
a
c
-
b
2
4
a
)].
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答案(点此获取答案解析)

解:(1)y=240-60
x
-
5
×20
,∴y=﹣4x+480(x≥60);(2)根据题意可得,x(﹣4x+480)=14000,解得,x1=

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阅读理解

    Why do we read poetry? First obvious one: because we enjoy it. The only other reason is for academic purposes, and that's not why this is here.

    Many of us read poetry simply because we often feel depressed and hopelessly lost, and in poetry we see how beautiful and strange everything is. So in that way poetry calms our anxiety.

    There are many different kinds of poems. They are not all calming. Some poems make me anxious, angry, scared, and sad, which is why I value them. As a reader, I want a full meal, not just dessert. I want the sweet and the bitter. Often, I read poetry when I'm already relaxed. In fact, I read more when I'm not stressed out.

    Here are the main reasons I respond to poetry, as far as I can tell. Metrical(格律的) poems are about setting up rules and then bending them. Usually, this is done by setting up a rhythm and then violating it or almost violating it. And then returning to it again. This satisfies my desire for order and also my desire for testing boundaries.

    Poetry plays with language and often slams words together in surprising ways, which is thrilling the way food can be when the chef has paired ingredients you never thought would taste good together but somehow do.

    Many poems are dense. Words mean two or three things at once and lots of suggestions are packed between the lines. This is intellectually inspiring and it allows me to read the same poem over and over always finding new things in it.

    And, of course, there's the subject matter. It interests me just as it would if the same subject was explored in a story or essay. Not all poems interest me in this way, but then not all stories and essays do, either.

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