【阅读材料】
把代数式通过配、凑等手段,得到局部完全平方式,再进行有关运算,这种解题方法叫做配方法 .配方法在因式分解、解方程、求最值等问题中都有着广泛的应用.
例1:用配方法分解因式:
.
解:原式![](https://staticzujuan.xkw.com/quesimg/Upload/formula/848087669b2f3e2ac18c8fb29706cdb3.png)
.
例2:用配方法求整式
的最小值.
解:
;
,
,
整式
的最小值为5.
【类比应用】
(1)如果整式
是一个完全平方式,则括号内的常数应为______;
(2)参考例1的步骤,用配方法分解因式:
;
(3)参考例2的步骤,用配方法求整式
的最小值.
把代数式通过配、凑等手段,得到局部完全平方式,再进行有关运算,这种解题方法叫做
例1:用配方法分解因式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f511654a6a5a93894b7337b7510b0d0c.png)
解:原式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/848087669b2f3e2ac18c8fb29706cdb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d7009e3c54bfbed40c444e263ea424e.png)
例2:用配方法求整式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dcfe32af170df7d4aadd4c22a8a9e36.png)
解:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ea533c52ef6ab19fc2ea0fdfeb2474e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/624896d972278b5a4fcd494658f7183e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ac33e64e4bb97af576c12a30596cdba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de0d10ef8b748d4531250c37c5d3f9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4dcfe32af170df7d4aadd4c22a8a9e36.png)
【类比应用】
(1)如果整式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85b8ef62d6f91fa1dbc2add16bfc5fdc.png)
(2)参考例1的步骤,用配方法分解因式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c744787abb48b017ee7c68b7bacc5c75.png)
(3)参考例2的步骤,用配方法求整式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edf626fb9737297663a5f21b8fc442d3.png)
23-24八年级上·湖北咸宁·期末 查看更多[3]
湖北省咸宁市咸安区2023-2024学年八年级上学期期末数学试题(已下线)第04讲 因式分解(知识解读+达标检测)-2023-2024学年七年级数学下册《知识解读·题型专练》(苏科版)(已下线)专题08 乘法公式与因式分解(考点清单+16种题型解读)-2023-2024学年七年级数学下学期期中考点大串讲(苏科版)
更新时间:2024-01-22 01:10:52
|
相似题推荐
解答题-证明题
|
适中
(0.65)
【推荐2】若ab=1,我们称a与b互为倒数,我们可以用以下方法证明
与
互为倒数:
方法一:∵
,∴
与
互为倒数.
方法二:∵
﹣1,∴
与
互为倒数.
(1)请你证明
与
互为倒数;
(2)若
,求
的值;
(3)利用“换元法”求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1f190b17530d81d927c358ac84757a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c34e01955f8c8fe2f0041b35d8d602a7.png)
方法一:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c03b841f235c6bab145a31c55602dab7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1f190b17530d81d927c358ac84757a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c34e01955f8c8fe2f0041b35d8d602a7.png)
方法二:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b24477e2df46eacbab9843436a882d48.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1f190b17530d81d927c358ac84757a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c34e01955f8c8fe2f0041b35d8d602a7.png)
(1)请你证明
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/105ab39914a6873ee48ed59d75f58e5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53204688086b1d0111e91cb49fa0ac61.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1e53d29581580311c1031c08797057d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a516b37e29d70e559fb912ed72e08463.png)
(3)利用“换元法”求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/de92a085822b98d78e3938986742ba2b.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐1】阅读理解学习:
将多项式
分解因式得
,说明多项式
有一个因式为
,还可知,当
时
.
请你学习上述阅读材料解答以下问题:
(1)若多项式
有一个因式为
,求
的值;
(2)若
,
是多项式
的两个因式,求
的值.
将多项式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96791c33798bd64168fbcfed8227e3d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65da8587d908407c4d2096c48b74f0d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96791c33798bd64168fbcfed8227e3d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/95e26ea0261f2b67983b07b8d0bb8bf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/815650356afb1f42207c27d3b11635f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/95ece4224e7c98233c55aa6608375a13.png)
请你学习上述阅读材料解答以下问题:
(1)若多项式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d215cad2e62cf95965826f8a77f823a3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa54d2a1b192048f8de9f66f0e14a1c1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39241f2eeccaa16d0550d851619bcb42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1b8d3f7a166ff5db92d9ee0014a960d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/89440840c169cde1bc60e4245fa98610.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/632244ea6931507f8656e1cc3437d392.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐2】阅读并解答:对于三次多项式
,我们把
代入多项式,发现
,由此可以推断多项式中有因式
,设另一个因式为
,多项式可以表示成
,整理得
,可得到
,
,所以
,
,把求出的
,
代入,就可以把多项式
因式分解.以上这种因式分解的方法叫“试根法”.对于多项式
,用“试根法”分解因式.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2717c81ca22824bf14ac7cfcc82aef2c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b384412acba251d87902ab928902f16.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a13c30f30c8fa28f872d64afc0b145f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b924d856924e8cf2b172d5cacffe0610.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad4556e574398a9ef6567e503c01cb9b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0abf1428adbd2be3b86c0a7744dd0e4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7ce02fd61294f7287faea407779c356.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45fb367f1f8184bffd6ad0d1849b63fa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ce4430b8b9b0c78de693513a7f88915.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b4d795709b0abcf47bceec2250f2f9b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ce4430b8b9b0c78de693513a7f88915.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2717c81ca22824bf14ac7cfcc82aef2c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd52bd8f1508badefc277a606561fef6.png)
您最近一年使用:0次