二元一次方程式(急)

[匿名]

2009-11-14 4:54 am

唔該要列明步驟~ =]
1.{x-y=0
{x+4y+1=0

2.{9m-n=1
{n-8m=3

3.{x-2y=5
{3x+y=-6

4.{2a+5b=3
{3a-b=13

下面既要用Elimination

5.{m+n=2
{m-n=8

6.{3x+y=9
{2x-y=6

7.{a+7b=9
{-6a-5b=20

8.{3x-2y=5
{2x+3y=12

9.{3x-7y=2
{7x-3y=18

10.{n-2m=4
{2m+9n=-24

11.{a+b=5
{4a-b=15

12.{4x-3y+1=0
{3x+y-9=0

13.{2x=3y
{x+2y-7=0

14.{3a-2b=10
{3b-4a=17

15.{10m+12n=-1
{9n-4m=5

16.{5a=2(-1-b)
{2a+5b=5

17.{18x+30y=17
{12x-18y=5

18.{3x+4y=18
{4x+3y=17

19.{2x-3y+7=0
{3x+2y+4=0

20.{3x+2y=12
{2x-y=1

21.{3x+2y+4=0
{2x-3y+7=0

22.{4x-7y=13
{4x+7y=-29

回答 (1)

太陽

2009-11-14 5:13 pm

✔ 最佳答案

1.{x-y=0............1
{x+4y+1=0.....2
from1,x=y.........3
Sub. 3 in 2
5x+1=0
Ans :x=y=-1/5

2.{9m-n=1........1
{n-8m=3........2
1+2:m=4
Sub.m=4 in 2,
n-32=3
n=35
Ans: m=4 n=35

3.{x-2y=5..........1
{3x+y=-6........2
from1,x=2y+5....3
Sub. 3 in 2,
7y+15=-6
y=-3
x=-1

4.{2a+5b=3.......1
{3a-b=13........2
from2,b=3a-13...3
sub.3 in 1
17a-65=3
a=4
b=-1

太多了,
二元一次方程式是可以用calculator的程式
請看
http://webcal.freetzi.com/3650P/simultaneous1.htm
example,
ax+by+c=0....1
dx+ey+f=0.....2
把a,b,c,d,e,f 順序輸入程式
答題方式:
ax+by+c=0....1
dx+ey+f=0.....2
by solving 1and 2
X=? and y=?

唔用calculator的程式會很煩

參考: http://webcal.freetzi.com/3650P/simultaneous1.htm

👍 0 👎 0