I have just learnt linear equation with 2 unknowns(which is extremely easy to me).
So I wonder how to solve equations with 3 unknowns, can some1 briefly explain
(better with examples, even I may not understand)?
Do I need 2 set up 3 equations, or it has other methods which I will learn in higher form?
At last, for most of the students, when do they usually learn this?
點計3個unknowns的equation?
2009-11-26 2:29 am
回答 (2)
2009-11-26 2:46 am
✔ 最佳答案
e.g.x + y + z = 14 ... (1)
x + y - z = 10 ... (2)
x - y + z = 6 ... (3)
First, (1) - (2),
z - (- z) = 14 - 10
2z = 4
z = 2
Then, (1) - (3),
y - (-y) = 14 - 6
2y = 8
y = 4
Finally,
x + y + z = 14
x + 4 + 2 = 14
x = 8
So, x = 8 , y = 4 , y = 2
Of course, this question is so easy but you have to know the basic step.
Then, you will know how to solve the challenging question.
2009-11-26 7:32 am
The idea is very simple actually.
"How many unknowns you have , how many equations you neeed to set"
For example, if there are 2009 unknows, you need to set 2009 equations!
The above idea will usually be teached in F.3-F.4
But it is good to know now
"How many unknowns you have , how many equations you neeed to set"
For example, if there are 2009 unknows, you need to set 2009 equations!
The above idea will usually be teached in F.3-F.4
But it is good to know now
參考: myself
收錄日期: 2021-04-19 20:41:55
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