聯立方程 代入消元方(請盡快回答)

圖片參考：https://s.yimg.com/lo/api/res/1.2/ZQit8r6YM3UMER1bF6V.OQ--/YXBwaWQ9dHdhbnN3ZXJzO3E9ODU-/http://i.imgur.com/ZH9B85L.gif

1.
{ x = 4y + 2 .....①
{ x + 2y = 8 .......②

把 ① 代入 ②：
(4y + 2) + 2y = 8
6y + 2 = 8
6y = 6
y = 1

代入 ①：
x = 4(1) + 2 = 6

即
{ x = 6
{ y = 1

✿ ❀ ✿ ❀ ✿ ❀ ✿ ❀ ✿ ❀ ✿ ❀ ✿ ❀ ✿ ❀ ✿ ❀ ✿ ❀ ✿ ❀ ✿ ❀ ✿ ❀ ✿ ❀ ✿ ❀

2.
{ x - y = 1 .....①
{ x + 2y = 4 .....②

從 ① 可知
x = y + 1 ...... ③

把 ③ 代入 ②：
(y + 1) + 2y = 4
3y + 1 = 4
3y = 3
y = 1

代入 ③：
x = 1 + 1 = 2

即
{ x = 2
{ y = 1



圖片參考：https://s.yimg.com/rk/HA00430218/o/1111101079.jpg

1.x=4y+2.....1
x+2y=8.......2
Sub(1)into(2)
4y+2+2y=8
6y=6
y=1
Sub y=1 into (1)
x=4(1)+2
x=6
So, x=6 and y=1

2.x-y=1.....1
x+2y=4.....2
From(1),
x=y+1.....3
Sub(3)into(2)
y+1+2y=4
3y=3
y=1
Sub y=1 into(1)
x-1=1
x=2
So, x=2 and y=1