如果<img class="kfformula" src="20190808/1565251013539366.png" data-latex="ab"/>，那么下列不等式正确的是（）

【单选题】

① <img class="kfformula" src="20190808/1565251013586057.png" data-latex="\frac {1} {2}a\frac {1} {2}b"/>

② <img class="kfformula" src="20190808/1565251013931183.png" data-latex="-3a-3b"/>

③ <img class="kfformula" src="20190808/1565251013130324.png" data-latex="5a5b"/>

④ <img class="kfformula" src="20190808/1565251013738499.png" data-latex="a-2b-2"/>

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【单选题】

不等式<img class="kfformula" src="20190808/1565250723184457.png" data-latex="{x}^{2}-2x-80"/>的解集是（）

① <img class="kfformula" src="20190808/1565250723229267.png" data-latex="\left ( {4,+\infty } \right )"/>

② <img class="kfformula" src="20190808/1565250723616994.png" data-latex="\left ( {-\infty ,-2} \right )\cup \left ( {4，+\infty } \right )"/>

③ <img class="kfformula" src="20190808/1565250723532354.png" data-latex="\left ( {-\infty ，-2} \right )"/>

④ <img class="kfformula" src="20190808/1565250723744347.png" data-latex="\left ( {-2,4} \right )"/>

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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】

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】

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】

<img class="kfformula" src="20190808/1565256388580621.png" data-latex="{25}^{\frac {3} {2}}="/>（）

① 5

② 125

③ 25

④ 50

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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】

<img class="kfformula" src="20190808/1565256297772060.png" data-latex="\sqrt {\left ( {lg5-1} \right )^{2}}"/>的值等于（）

① <img class="kfformula" src="20190808/1565256297983776.png" data-latex="lg\frac {1} {5}"/>

② <img class="kfformula" src="20190808/1565256297148379.png" data-latex="lg5-1"/>

③ <img class="kfformula" src="20190808/1565256297764160.png" data-latex="lg5"/>

④ <img class="kfformula" src="20190808/1565256297303551.png" data-latex="lg2"/>

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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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【单选题】

下列函数中，在区间<img class="kfformula" src="20190808/1565255863544549.png" data-latex="\left ( {-\infty ，+\infty } \right )"/>内为增函数的是（）

① <img class="kfformula" src="20190808/1565255863279980.png" data-latex="y=2-x"/>

② <img class="kfformula" src="20190808/1565255863845028.png" data-latex="y={3}^{x}"/>

③ <img class="kfformula" src="20190808/1565255863797150.png" data-latex="y={x}^{-2}"/>

④ <img class="kfformula" src="20190808/1565255863844363.png" data-latex="y={log}_{0.3}x"/>

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