今有360本图书借给学生阅读，每人9本，则余下的书数<img class="kfformula" src="20190924/1569292387333325.png" data-latex="y"/>（本）和学生数<img class="kfformula" src="20190924/1569292387869597.png" data-latex="x"/>（个）之间的函数关系式为( )

【单选题】

① <img class="kfformula" src="20190924/1569292387325349.png" data-latex="y=40/x"/>

② <img class="kfformula" src="20190924/1569292387912197.png" data-latex="y=9*x"/>

③ <img class="kfformula" src="20190924/1569292387266041.png" data-latex="y=360-9x"/>

④ <img class="kfformula" src="20190924/1569292387456376.png" data-latex="y=360+9x"/>

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【单选题】

已知<img class="kfformula" src="20190809/1565322050560879.png" data-latex="A\left ( {0，-2} \right )"/>，<img class="kfformula" src="20190809/1565322050489966.png" data-latex="B\left ( {x，6} \right )"/>的中点坐标为<img class="kfformula" src="20190809/1565322050782302.png" data-latex="\left ( {-1，y} \right )"/>，则<img class="kfformula" src="20190809/1565322050701271.png" data-latex="x"/>，<img class="kfformula" src="20190809/1565322050277662.png" data-latex="y"/>的值分别为（）

① <img class="kfformula" src="20190809/1565322050358526.png" data-latex="x=-4，y=-2"/>

② <img class="kfformula" src="20190809/1565322050607462.png" data-latex="x=2，y=4"/>

③ <img class="kfformula" src="20190809/1565322050656212.png" data-latex="x=-4，y=25"/>

④ <img class="kfformula" src="20190809/1565322050205695.png" data-latex="x=-2，y=2"/>

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【单选题】

等差数列<img class="kfformula" src="20190809/1565317844150977.png" data-latex="\left \{ {{a}_{n}} \right \} "/>的首项<img class="kfformula" src="20190809/1565317844698638.png" data-latex="{a}_{1}=-2"/>，<img class="kfformula" src="20190809/1565317844536248.png" data-latex="{S}_{3}=3"/>，那么（）

① <img class="kfformula" src="20190809/1565317844862924.png" data-latex="d=3"/>

② <img class="kfformula" src="20190809/1565317844935823.png" data-latex="d=2"/>

③ <img class="kfformula" src="20190809/1565317844903124.png" data-latex="d=-2"/>

④ <img class="kfformula" src="20190809/1565317844953331.png" data-latex="d=-3"/>

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【单选题】

两条平行直线<img class="kfformula" src="20190809/1565322829875215.png" data-latex="3x+4y-7=0"/>和<img class="kfformula" src="20190809/1565322829154016.png" data-latex="3x+4y+8=0"/>之间的距离是（）

① <img class="kfformula" src="20190809/1565322829886592.png" data-latex="3"/>

② <img class="kfformula" src="20190809/1565322829721740.png" data-latex="3\sqrt {2}"/>

③ <img class="kfformula" src="20190809/1565322829406438.png" data-latex="15"/>

④ <img class="kfformula" src="20190809/1565322829833725.png" data-latex="\frac {1} {5}" width="87" height="63"/>

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【单选题】

二次函数<img class="kfformula" src="20190808/1565254258613538.png" data-latex="y={x}^{2}+mx+6"/>的顶点<img class="kfformula" src="20190808/1565254258861129.png" data-latex="\left ( {-1,5} \right )"/>，则<img class="kfformula" src="20190808/1565254258615064.png" data-latex="m"/>的值为（）

① 2

② 5

③ -2

④ -5

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【单选题】

<img class="kfformula" src="20190730/1564475645410465.png" data-latex="{5}^{-1}"/>等于（）

① <img class="kfformula" src="20190730/1564475645509248.png" data-latex="-\frac {1} {5}" width="96" height="63"/>

② <img class="kfformula" src="20190730/1564475645473521.png" data-latex="\frac {1} {5}" width="94" height="63"/>

③ <img class="kfformula" src="20190730/1564475645939907.png" data-latex="-5"/>

④ <img class="kfformula" src="20190730/1564475645707520.png" data-latex="5"/>

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【单选题】

<img class="kfformula" src="20190809/1565313651838733.png" data-latex="\sqrt {7}+\sqrt {3}"/>与<img class="kfformula" src="20190809/1565313651801618.png" data-latex="\sqrt {7}-\sqrt {3}"/>的等比中项是（）

① <img class="kfformula" src="20190809/1565313651278262.png" data-latex="4"/>

② <img class="kfformula" src="20190809/1565313651577788.png" data-latex="\pm 4"/>

③ <img class="kfformula" src="20190809/1565313651689008.png" data-latex="\pm 2"/>

④ <img class="kfformula" src="20190809/1565313651298877.png" data-latex="2"/>

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【单选题】

等差数列<img class="kfformula" src="20190809/1565315219717157.png" data-latex="\left \{ {{a}_{n}} \right \} "/>首项<img class="kfformula" src="20190809/1565315219801596.png" data-latex="{a}_{1}=1"/>，公差<img class="kfformula" src="20190809/1565315219560191.png" data-latex="d=-3"/>，当<img class="kfformula" src="20190809/1565315219192999.png" data-latex="{a}_{n}=-56"/>时，项数<img class="kfformula" src="20190809/1565315219715609.png" data-latex="n"/>等于（）

① 18

② 19

③ 20

④ 21

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【单选题】

函数<img class="kfformula" src="20190808/1565253438624934.png" data-latex="y=2-{x}^{2}"/>的单调递减区间是（）

① <img class="kfformula" src="20190808/1565253438467999.png" data-latex="\left ( {-\infty ，0} \right )"/>

② <img class="kfformula" src="20190808/1565253438403956.png" data-latex="\left ( {-\infty ，-1} \right )"/>

③ <img class="kfformula" src="20190808/1565253438303182.png" data-latex="\left ( {-1，+\infty } \right )"/>

④ <img class="kfformula" src="20190808/1565253438117832.png" data-latex="\left ( {0，+\infty } \right )"/>

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【单选题】

在数列<img class="kfformula" src="20190809/1565316783973080.png" data-latex="\left \{ {{a}_{n}} \right \} "/>中，前<img class="kfformula" src="20190809/1565316783992384.png" data-latex="n"/>项和公式是<img class="kfformula" src="20190809/1565316783683277.png" data-latex="{s}_{n}=4{n}^{2}-n"/>，那么<img class="kfformula" src="20190809/1565316783325652.png" data-latex="{a}_{2}"/>为（）

① 3

② 17

③ 11

④ 14

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