1.单选题- (共13题)

A.2个 | B.3个 | C.4个 | D.5个 |

A. 2∠A=∠1﹣∠2 B. 3∠A=2(∠1﹣∠2) C. 3∠A=2∠1﹣∠2 D. ∠A=∠1﹣∠2

A.∠D=∠C,∠BAD=∠ABC | B.∠BAD=∠ABC,∠ABD=∠BAC |
C.BD=AC,∠BAD=∠ABC | D.AD=BC,BD=AC |

A.83 | B.84 | C.85 | D.86 |
2.选择题- (共2题)
根据短文理解,回答下列问题。
A mother planted many kinds of vegetables in her garden. One morning she said to her daughter. “Betty, come here. Look at all these little yellow marks on the leaves of the cabbages. They are eggs of a kind of insects. They are very beautiful but very bad for cabbages. This afternoon you must find all the eggs on the leaves and kill them. In this way, you will help us have better greener and bigger cabbages.”
Betty didn't think she should do it at once and in the end she forgot all about it. Her mother was ill for a few days and couldn't work in her garden. When she was well, she took Betty to the garden to see the cabbages. To their surprise, the insects had eaten up every leaf. When Betty saw this, she was upset and began to cry. Then her mother said to her, “We should never put off what we have to do today till tomorrow. And you must learn to deal with the things while they are small. or it will turn into a big problem.”
3.填空题- (共6题)
4.解答题- (共8题)
我们把多项式a2+2ab+b2及a2﹣2ab+b2叫做完全平方式,如果一个多项式不是完全平方式,我们常做如下变形:先添加一个适当的项,使式子中出现完全平方式,再减去这个项,使整个式子的值不变,这种方法叫做配方法.配方法是一种重要的解决问题的数学方法,不仅可以将一个看似不能分解的多项式分解因式,还能解决一些与非负数有关的问题或求代数式最大值,最小值等.
例如:分解因式x2+2x﹣3=(x2+2x+1)﹣4=(x+1)2﹣4=(x+1+2)(x+1﹣2)=(x+3)(x﹣1);
再例如求代数式2x2+4x﹣6的最小值.2x2+4x﹣6=2(x2+2x﹣3)=2(x+1)2﹣8.可知当x=﹣1时,2x2+4x﹣6有最小值,最小值是﹣8,根据阅读材料用配方法解决下列问题:
(1)分解因式:m2﹣4m﹣5= .
(2)当a,b为何值时,多项式a2+b2﹣4a+6b+18有最小值,并求出这个最小值.
(3)已知a,b,c为△ABC的三边,且满足a2+2b2+c2﹣2b(a+c)=0,试判断此三角形的形状.
A.![]() (1)求证:△BCD为等腰三角形; (2)若∠BAC的平分线AE交边BC于点E,如图2,求证:BD+AD=AB+BE; (3)若∠BAC外角的平分线AE交CB延长线于点E,请你探究(2)中的结论是否仍然成立?直接写出正确的结论. |
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【1】题量占比
单选题:(13道)
选择题:(2道)
填空题:(6道)
解答题:(8道)
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【2】:难度分析
1星难题:0
2星难题:0
3星难题:0
4星难题:1
5星难题:0
6星难题:7
7星难题:0
8星难题:7
9星难题:12