請問有冇人識以下的數?
回答 (6)
2008-01-20 7:00 pm
✔ 最佳答案
請問有冇人識以下的數? A君用31元買了4個蘋果及5個梨, B君用32元買了5個蘋果及4個梨, 如果買1個蘋及1個梨要多少錢? 請將算式列出!!!!!!!!!
ans:
4X+5Y=31
5X+4Y=32
9X+9Y=63
X+Y=7
X = apple and Y = pear.
2008-01-21 8:09 pm
31 = 4a+5p ----- (1)
32 = 5a+4p ----- (2)
a+p = ?
(2) - (1) :
1 = a - p
a = p + 1 ----- (3)
Sub. (3) into (2) :
32 = 5(p+1)+4p
32 = 9p+5
p = (32-5)/9 = 27/9 = 3
a = p+1 = 3+1 = 4
買1個蘋及1個梨要(a+p) = 3+4 = 7元
32 = 5a+4p ----- (2)
a+p = ?
(2) - (1) :
1 = a - p
a = p + 1 ----- (3)
Sub. (3) into (2) :
32 = 5(p+1)+4p
32 = 9p+5
p = (32-5)/9 = 27/9 = 3
a = p+1 = 3+1 = 4
買1個蘋及1個梨要(a+p) = 3+4 = 7元
2008-01-20 8:19 pm
let x=蘋果,y=梨
4x+5y=31-----------(1)
5x+4y=32-----------(2)
(1)*5 20x+25y=155
(2)*4 20x+16y=128
20x+25y=155
-20x+16y=128
9y=27
y=3
put y=3 into (1)
4x+5(3)=31
4x=16
x=4
所以1個蘋果要4元，1個梨要3元
4x+5y=31-----------(1)
5x+4y=32-----------(2)
(1)*5 20x+25y=155
(2)*4 20x+16y=128
20x+25y=155
-20x+16y=128
9y=27
y=3
put y=3 into (1)
4x+5(3)=31
4x=16
x=4
所以1個蘋果要4元，1個梨要3元
2008-01-20 2:55 pm
system:
4X+5Y=31
5X+4Y=32
9X+9Y=63
X+Y=7
X = apple and Y = pear.
4X+5Y=31
5X+4Y=32
9X+9Y=63
X+Y=7
X = apple and Y = pear.
2008-01-20 10:40 am
let A=蘋果, B=梨
4A+5B=31
5A+4B=32
將兩式相加
9A+9B=63
9(A+B)=63
A+B=63/9=7
4A+5B=31
5A+4B=32
將兩式相加
9A+9B=63
9(A+B)=63
A+B=63/9=7
參考: Me~
2008-01-20 10:10 am
let x=蘋果, y=梨
4x+5y=31
5x+4y=32
9x+9y=63
x+y=6
4x+5y=31
5x+4y=32
9x+9y=63
x+y=6
收錄日期: 2021-04-14 18:31:06
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080120000051KK00415