數學題列式
回答 (2)
2010-06-04 5:31 am
✔ 最佳答案
x是紅書包:30x+25(20-x)=540
30x+500-25x=540
5x =40
x =8
2010-06-04 5:35 am
設紅色書包 r 個 & 黃色書包 y 個
{ r +y = 20 ----- i
{ 30r + 25y = 540 ----- ii
i,
r = 20 - y ---- iii
Sub iii in ii,
30r + 25y = 540
30 (20- y) + 25y = 540
600 - 30y + 25y = 540
600 - 5y = 540
600 - 540 = 5y
60 = 5y
y = 12 ---- iv
Sub iv in i,
r + y = 20
r + 12 = 20
r = 8
所以紅色書包有8個 & 黃色書包有12個.
{ r +y = 20 ----- i
{ 30r + 25y = 540 ----- ii
i,
r = 20 - y ---- iii
Sub iii in ii,
30r + 25y = 540
30 (20- y) + 25y = 540
600 - 30y + 25y = 540
600 - 5y = 540
600 - 540 = 5y
60 = 5y
y = 12 ---- iv
Sub iv in i,
r + y = 20
r + 12 = 20
r = 8
所以紅色書包有8個 & 黃色書包有12個.
參考: me
收錄日期: 2021-04-23 18:24:54
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