找规律

第一个框框右下角是3

果然高手啊！感激加膜拜

x+2y+3z=20.      (1)
3x+4y+2z=26.    (2)
y+4z=19.            (3)
-2(3)+(1)
x-5z=  -18.    (4)
-4(3)+2
3x-14z= -50.  (5)
-3(4)+(5)
Z=4
代入（4）

X=2
代入（3）
y=3

2x2+4x3+3x4=28

1A + 2B + 3C =20
3A + 4B + 2C =26
        1B + 4C =19

-------------------------------

2A + 4B + 3C = ??


solve the three equations above, to get A, B, and C. Then answer ?? is 28.

请两位高手详解，谢谢！
三元一次方程也在初一奥数范围之内。

老陈 发表于 2013-8-23 09:23
I knew why. Make 3 equitions and solve them. Put into last square.

Ah, "san yuan yi ci fang cheng"

//bow   grandmaster makes difficult problem easy and straight forward.

I knew why. Make 3 equitions and solve them. Put into last square.

wudihulu 发表于 2013-8-23 02:52
Ok, I won't ask you why, but how did you get that number? Thanks.

I used preliminary linear algebra, which I suspect is not within the range of grade 7.

If you want to use the mathematics in grade 7 to solve this, I can not help.

O btw, I do not garantee the answer is correct.  {:soso_e137:}

我瞎蒙一下：28

maomaobiao 发表于 2013-8-22 14:49
28

Don't ask me why

Ok, I won't ask you why, but how did you get that number? Thanks.