解二元一次方程组计算题.docx

f9x+4y=35
[8x+3y=30
f7x+2y=52
[7x+4y=62
f 4x+6y=54 j 9x+2y=87
J 2x+y=7
I 2x+5y=19
fx+2y=21
13x+5y=56
I 5x+7y=522- + -5- — T
3(2x + 3v) 6(3x + 2v)
=
二、解方程组
%4- y-z = 4
、＜2i—y+z = 5
x — 3y + z — —2
3尤-2y = 8
2、 ＜ 2y + 3z = 1
x + 5z = 7
x-b 2y - z = 6
3、 ＜ 2x + y + z = 9
3x + 4y + z = 18
x+ y-z = 0
4、 〈2尤+y + z = 7
x-3y+z=8
2002v-2003y = 2005
200k-2002y = 2004
2005r + 2007y = 6019
2007r+2005y = 6017
)『-3y = 5
2x + y = 5
(2)
y = x-3 y-2x = 5
2x-y = 5
[x+ y = 1
x-2y = 0
•X = 3y+ 1
9m -2n = 3
⑸\
4n + m = —l
(6) J
2p — 3g = 13 一 p + 5 = 4q
3m -2n = 5
(1) \
4m + 2〃 = 9
(2) ＜
3尤-5y = 7
4x + 2y = 5
6x-5y = 11
⑶\ 7
-4x-4y = 7
1 lx-9y = 12
(4) i
一4尤+ 3y = -5
1 1 2
(5)〈5 3 5
- =
4m 一 2〃 + 5 = 0
1、<
3n 一 4m = 6
(6)
2、
[ + =
3、<
llx-10y = l
4、
5、
-2x — lly = 3c 6x+ 29y = -7 c
（。为常数）
6、
x-2y = Q
3x + 2y = 8
3x + 4y = 2
2x- y = 5
5x + 2y = 5。
〔3"4； = q其中。为常数）
-X-^y=\
2 3
1 2
——工一 y =—
L 3 3
2 1 |八
—x ——y+ 1 = 0
< 5 3
2x + 2y = 7
-x-4y = 3c-\-d
<
4x + 3y = 2d-c
（c、d为常数）
2X— ' q
5
£±2 = 3
3
a + b = 3
(4) < q + c = 4
Z? + c = 5
（用代入法）
3x — 2y = —2 2x + 3y = 6
‘33-l) = y + 5
Zzl = J
I 3 5
x-2y =-3
2x + 3y - z = 5
3x + y + 2z = 11
3x-5z = 6 ①
x + 4z = -15 ②
x + 2y = 150 (1)
* + 3y = 300 (2)
3x+7y = 9 (1)
*-7y = 5 (2)
m-n=2 ①
2m + 3〃 = 14 ②
40_y_l) = 3(l_y)_2
x y
- + - = 2
〔2 3
m
n
=13
一 +
2
3
m
n
=3
4
3x + 2y = 5 2x-y = S
x 1
y = -1 4
x + 4y = 4
3(x+ y)_4(]_ y) = 4
x+ y x-y <
——+—— =1
I 2 6 x y
- + - = 2
3 4
3x-4y = -7
x—l y+2 n
3 4
x-3 y-1 _1
二 ~ 6
用代入法解
x = 3y
2x-5y = 4-
用加减法解＜
2x + 3y = 15 2x-2y = 5
3x-5y = 9 2x + 3y = -6
/ 、 5x + y = 7
(1) \ 7
4x — 3y = 17
4x - 3y = 5
2x-y = 2
y - z = 13