解下列聯立方程:
(x+1)(y-3)=0-----------1
2x+y=5-----------------2
中4數學.解下列聯立方程.唔該大家列詳細既步驟啊.唔該大家^^
2008-05-16 5:00 am
回答 (3)
2008-05-16 5:31 am
✔ 最佳答案
由條件(1)(x+1)(y-3)=0得(x+1)=0 或 (y-3)=0
若(x+1)=0﹐則x=-1
代入(2)
y=5-2x=5+2=7
x=-1,y=7
若(y-3)=0﹐則y=3
代入(2)
x=(1/2)(5-y)=(1/2)(5-3)=1
x=1,y=3
2008-05-17 6:05 am
(x+1)(y-3) = 0...(1)
2x+y = 5...(2)
From (1)
x+1 = 0 or y - 3 = 0
x = -1 or y = 3
when x = -1
2x + y = 5...(2)
2(-1) + y = 5
y - 2 = 5
y = 7
therefore, x = -1, y = 7//
when y = 3
2x + y = 5...(2)
2x + 3 = 5
x = 1
therefore, x = 1, y = 3//
2x+y = 5...(2)
From (1)
x+1 = 0 or y - 3 = 0
x = -1 or y = 3
when x = -1
2x + y = 5...(2)
2(-1) + y = 5
y - 2 = 5
y = 7
therefore, x = -1, y = 7//
when y = 3
2x + y = 5...(2)
2x + 3 = 5
x = 1
therefore, x = 1, y = 3//
2008-05-16 5:36 am
from (2)
y = 5 - 2x ---- (3)
sub (3) to (1)
(x+1)[(5-2x)-3]=0
(x+1)(2-2x)=0
2(x+1)(1-x)=0
x+1 = 0 or 1-x = 0
x = -1 or x = 1
y = 5 - 2x ---- (3)
sub (3) to (1)
(x+1)[(5-2x)-3]=0
(x+1)(2-2x)=0
2(x+1)(1-x)=0
x+1 = 0 or 1-x = 0
x = -1 or x = 1
收錄日期: 2021-04-25 16:57:51
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