求解二元一次方程应用题的技巧!!

我说的是二元一次方程组应用题……-_-*
2025-03-21 17:42:24
推荐回答(5个)
回答1:

1、常见的行程问题可分为四种情况,它们分别是:平路;上、下坡路;环路;水路。常见的行程问题分成两大类型:相遇问题和追击问题。

(1)相遇问题:两人从不同地点出发,相向而行,直到相遇。

(2)追击问题:

①两人同地不同时,同向而行,直到后者追上前者,其等量关系是:两人所走路程相等,(两人所用时间不同)

②两人同时不同地,同向而行,直到后者追上前者,其等量关系是:两人所走的路程之差等于已知两地距离。(两人所用时间相同)

③两人不同时不同地,同向而行,直到后者追上前者,其等量关系是:两人所走路程之差等于两地的距离。(两人所用时间不同)

注意环路与直路的区别,例如在环路问题中,若两人同时同地出发,同向而行,当第一次相遇时,两人所走路程差为一周长。

水路行船问题:顺水速度 =静水速度+水流速度;

逆水速度=静水速度-水流速度。

解行程问题的应用题时,通常采用线段图或列表进行分析,从而正确地找出等量关系,列出方程(组)解决问题。

2、解有关增长率问题时,要掌握下面的基本等量关系式:

原量×(1+增长率)=增长后的量,

原量×(1-减少率)=减少后的量。

3、解有关配套问题,要根据配套的比例,依据特定的数量关系列方程(组)求解题。

4、含有两个未知量的应用题,一般列出二元一次方程组比列一元一次方程要容易些,解应用题时要养成检
验的良好习惯,一是检验所求得解是否符合方程组,二是检验是否符合实际意义。

回答2:

关于这类题,其实很简单的,一定要说清和话很难,因为题不做不完的,只能告诉你一些基常识了
属先你得明白你做的是一个二元一次方程题,而所谓二元一次,二元是指两未知数,一次是说每个未知数其指数为1 例如一次 x 二次 x2
而二元一次组,就是联立两个二元一次方程,这有一个方法,因为每个二元一次方程都是一个等式,所以题中必有两个或以上的相等关系存在,你找出来设两个未知道表示未知量然立等式记住二元一次方程组,记住二元一次组中两个等式中的未知道都是相同的就是说一个式中的一个未知数与另一个式中的相同

回答3:

首先要读懂题意,找出等量关系式!

一般情况下,直接设两个未知数就好了,然后根据条件列出方程式!

所以就不要管方程式难不难解,先列出方程再说!呵!

找出关系式是最重要的,所以一定要把题目看懂才好!

慢慢练习的话,会有提高的!

回答4:

正确选择未知数,列出方程
在解答过程中灵活运用代入法和加减法进行消元

回答5:

主要是找出等量关系

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