解方程或不等式组:
(1)
;
(2)
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ccf1328602bd22b09ca55faa023a3d3.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/093f199b0bf45ed2c65ddc624e456673.png)
更新时间:2023-01-08 13:40:28
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解答题-计算题
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适中
(0.65)
【推荐1】(1)计算:﹣24﹣
+|1﹣4sin60°|+(π﹣
)0;
(2)解方程:2x2﹣4x﹣1=0.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cde029ac94c601540583c64bc48c17bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf31876698721a199c7c53c6b320aa86.png)
(2)解方程:2x2﹣4x﹣1=0.
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解答题-问答题
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适中
(0.65)
名校
【推荐2】我们把形如
的多项式叫做关于x的二次三项式.在了解了形如
的二次三项式分解因式的方法的基础上,现在介绍利用求出一元二次方程的根的方法,将一般的二次三项式在实数范围内分解因式.
,这就是说,在分解
二次三项式
的因式时,可先求出方程
的两个根
,然后再写成![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c389812eb9acd47b9683436c49d14ff3.png)
例:在实数范围内分解因式:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96d5147ff26eb4aa262af671f8f5f551.png)
解:∵
的根为
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7f72de8f685fd7330f3d9ef97cff439.png)
∴![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a0e73ebc664f7506c47bb3c66f7df51.png)
试仿照上例在实数范围分解因式:
(1)
;
(2)
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e600c20cd4be3321dc5ea832833d1aeb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3cc42b5aed58bcfc052aaadc2dd11897.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea689c2a7f386af185ceafd477a861c3.png)
二次三项式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e600c20cd4be3321dc5ea832833d1aeb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13fa32c1e926f40a0722d106563777ef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd8ca3aa2d1ba52e82613d0d65d800e7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c389812eb9acd47b9683436c49d14ff3.png)
例:在实数范围内分解因式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96d5147ff26eb4aa262af671f8f5f551.png)
解:∵
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d9db284f56ed1260e700830e7e9205b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef87a280e53df041bb4ac08ee2c7db6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7f72de8f685fd7330f3d9ef97cff439.png)
∴
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a0e73ebc664f7506c47bb3c66f7df51.png)
试仿照上例在实数范围分解因式:
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c289fb050269530042eb70f407879cae.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0894cecb101547e65debed24aab58af.png)
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