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#1
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ªèÇÂá¡é¢é͹Õé˹èͤÃѺ
ãËé $w + x + y + z = 50$ áÅéÇ $w - 4 = x + 4$ áÅÐ $ y = 4z $ ¨§ËÒ $w + x$
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#2
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äÁèÁÕã¤ÃµÍºáÇÐà¢éÒÁÒ·Ñ¡·Ò¤ÃѺ
⨷Âì¶éÒÁÕà§×è͹ä¢á¤è¹Õé¡çÁÕËÅÒ¤ӵͺ¤ÃѺ |
#3
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4µÑÇá»Ã 3ÊÁ¡ÒÃÁÕËÅÒ¤ӵͺ
â´ÂãªéÊÁ¡ÒÃÍÔ§µÑÇá»ÃàÊÃÔÁ $w+x+y+z=50$ -----------------------(1) $w-x=8$-------------------------------(2) $y=4z$---------------------------------(3) á·¹(3)ã¹ (1) $w+x+5z=50$------------------------(4) ¨Ò¡ (2) ¨Ðä´é $w=x+8$ ᷹㹠(4) $2x+5z=42$ ãËé z=t ¨Ðä´é $x=\frac{42-5t}{2}$ á·¹¤èÒã¹ w=x+8 ä´é $w=\frac{58-5t}{2}$ ´Ñ§¹Ñé¹ $(x,y,z,w)=(\frac{42-5t}{2},4t,t,\frac{58-5t}{2})$ $w+x=50-5t$ (¨ÃÔ§æ¨ÐµÍºÇèÒw+x=50-5z¡çä´é¹Õèà¹ÍÐ) 14 ¡Ã¡®Ò¤Á 2010 00:04 : ¢éͤÇÒÁ¹Õé¶Ù¡á¡éä¢áÅéÇ 1 ¤ÃÑé§, ¤ÃÑé§ÅèÒÊØ´â´Â¤Ø³ poper |
#4
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¼ÁàʹÍÇÔ¸Õ¡ÒÃÁͧ¤ÓµÍºáºº¤ÃèÒÇæÇèÒÁÕËÅÒ¤ӵͺËÃ×ÍäÁè ¨Ò¡â¨·Âì·Õè¡Ó˹´ãËé
$w-4=x+4=k$ ⨷Âìµéͧ¡ÒöÒÁ $2k$ ´Ñ§¹Ñ鹨Ðä´éÇèÒ $w-4+x+4+4z+z =50$ $\therefore 2k = 50-5z$ ⨷ÂìäÁèä´é¡Ó˹´¤ÇÒÁÊÑÁ¾Ñ¹¸ì¡Ñ¹ÃÐËÇèÒ§ z ¡Ñº k ¡çáÊ´§ÇèÒàÃÒà»ÅÕ蹤èÒä´éµÒÁ㨪ͺ¢Í§µÑÇã´µÑÇ˹Öè§ |
#5
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¢Íº¤Ø³ÁÒ¡¤ÃѺ
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#6
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ÍéÒ§ÍÔ§:
¨Ðä´éÇèÒ$w=x+8$ áÅШҡ$y = 4z$ á·¹ã¹$w + x + y + z = 50 \rightarrow w + x= 50-5z \rightarrow 2x =42-5z \rightarrow x= 21-\frac{5z}{2} $ ¨Ò¡µÃ§¹ÕéàÃÒÃÙéä´éàÅÂÇèÒ $z$µéͧà»ç¹àÅ¢¤Ùè àÃÒËҢͺࢵ¢Í§$z$µèÍ $21-\frac{5z}{2}>0$ $z<\frac{42}{5} $ à¹×èͧ¨Ò¡àÃÒ¡Ó˹´ãËé$z$à»ç¹¨Ó¹Ç¹àµçÁºÇ¡áÅÐà»ç¹àÅ¢¤Ùè ¨Ðä´éÇèÒ$z\leqslant 8$ ä´éá¡è $2,4,6,8$ $z=2, \rightarrow w+x=40$ $z=4 \rightarrow w+x=30$ $z=6 \rightarrow w+x=20$ $z=8 \rightarrow w+x=10$ ¶éÒäÁè¡Ó˹´ÇèÒ$w,x,y,z$à»ç¹¨Ó¹Ç¹¹Ñº(¨Ó¹Ç¹àµçÁºÇ¡) ¤ÓµÍº¤§ÁÕÁÒ¡ÁÒ¡ÇèÒ¹Õé¤ÃѺ
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