½â£º£¨1£©¡ßÅ×ÎïÏß¹ýÔµãO£¬ÇÒÓëxÖá½»ÓÚÁíÒ»µãA£¨AÔÚOÓҲࣩ£¬OA=3£¬
¡àAµã×ø±êΪ£¨3£¬0£©£¬
¡àÅ×ÎïÏߵĶԳÆÖáΪֱÏßx=
![](http://thumb.1010pic.com/pic5/latex/33.png)
£»
£¨2£©¡ßÅ×ÎïÏߵĶԳÆÖáΪֱÏßx=
![](http://thumb.1010pic.com/pic5/latex/33.png)
£¬
¡à¿ÉÉèÅ×ÎïÏߵĽâÎöʽΪy=a£¨x-
![](http://thumb.1010pic.com/pic5/latex/33.png)
£©
2+k£¬
¡à¶¥µãBµÄ×ø±êΪ£¨
![](http://thumb.1010pic.com/pic5/latex/33.png)
£¬k£©£®
Èçͼ1£¬¡ßµãCµÄºá×ø±êΪ£ºON=
![](http://thumb.1010pic.com/pic5/latex/33.png)
+3=
![](http://thumb.1010pic.com/pic5/latex/190.png)
£¬µãCÔÚÅ×ÎïÏßy=a£¨x-
![](http://thumb.1010pic.com/pic5/latex/33.png)
£©
2+kÉÏ£¬
¡àµãCµÄ×Ý×ø±êΪa£¨
![](http://thumb.1010pic.com/pic5/latex/190.png)
-
![](http://thumb.1010pic.com/pic5/latex/33.png)
£©
2+k=9a+k£®
![](http://thumb.1010pic.com/pic5/upload/201310/528502831b4bd.png)
¡ßMC=4.5£¬
¡à9a+k-k=4.5£¬
¡àa=
![](http://thumb.1010pic.com/pic5/latex/13.png)
£¬
½«Aµã×ø±ê£¨3£¬0£©´úÈëy=
![](http://thumb.1010pic.com/pic5/latex/13.png)
£¨x-
![](http://thumb.1010pic.com/pic5/latex/33.png)
£©
2+k£¬
µÃ
![](http://thumb.1010pic.com/pic5/latex/13.png)
£¨3-
![](http://thumb.1010pic.com/pic5/latex/33.png)
£©
2+k=0£¬½âµÃk=-
![](http://thumb.1010pic.com/pic5/latex/4491.png)
£¬
¡àÅ×ÎïÏߵĽâÎöʽΪy=
![](http://thumb.1010pic.com/pic5/latex/13.png)
£¨x-
![](http://thumb.1010pic.com/pic5/latex/33.png)
£©
2-
![](http://thumb.1010pic.com/pic5/latex/4491.png)
£¬¼´y=
![](http://thumb.1010pic.com/pic5/latex/13.png)
x
2-
![](http://thumb.1010pic.com/pic5/latex/33.png)
x£»
£¨3£©Å×ÎïÏߵĶԳÆÖáÉÏ´æÔÚʹ¡÷ACDÖܳ¤×îСµÄµãD£¬ÀíÓÉÈçÏ£º
Èçͼ1£¬Á¬½ÓOC£¬½»Å×ÎïÏߵĶԳÆÖáÓÚµãD£¬Ôò¡÷ACDµÄÖܳ¤=AC+AD+CD=AC+OD+CD=AC+OC×îС£®
ÉèÖ±ÏßOCµÄ½âÎöʽΪy=mx£¬½«µãCµÄ×ø±ê£¨
![](http://thumb.1010pic.com/pic5/latex/190.png)
£¬
![](http://thumb.1010pic.com/pic5/latex/24635.png)
£©´úÈ룬
µÃ
![](http://thumb.1010pic.com/pic5/latex/190.png)
m=
![](http://thumb.1010pic.com/pic5/latex/24635.png)
£¬½âµÃm=
![](http://thumb.1010pic.com/pic5/latex/365.png)
£¬
¼´Ö±ÏßOCµÄ½âÎöʽΪy=
![](http://thumb.1010pic.com/pic5/latex/365.png)
x£¬
µ±x=
![](http://thumb.1010pic.com/pic5/latex/33.png)
ʱ£¬y=
![](http://thumb.1010pic.com/pic5/latex/365.png)
¡Á
![](http://thumb.1010pic.com/pic5/latex/33.png)
=
![](http://thumb.1010pic.com/pic5/latex/4491.png)
£®
¹ÊËùÇóDµã×ø±êΪ£¨
![](http://thumb.1010pic.com/pic5/latex/33.png)
£¬
![](http://thumb.1010pic.com/pic5/latex/4491.png)
£©£»
£¨4£©ÌÝÐÎEFGHµÄÃæ»ýSÓëÏ߶ÎEFµÄ³¤¶È´æÔÚº¯Êý¹Øϵ£¬ÀíÓÉÈçÏ£º
Èçͼ2£¬ÉèµãEºá×ø±êΪa£¬ÔòEµã×ø±êΪ£¨a£¬
![](http://thumb.1010pic.com/pic5/latex/13.png)
a
2-
![](http://thumb.1010pic.com/pic5/latex/33.png)
a£©£¬Hµã×ø±êΪ£¨a£¬0£©£¬
µãFºá×ø±êΪa+3£¬Fµã×ø±êΪ£¨a+3£¬
![](http://thumb.1010pic.com/pic5/latex/13.png)
£¨a+3£©
2-
![](http://thumb.1010pic.com/pic5/latex/33.png)
£¨a+3£©£©£¬Gµã×ø±êΪ£¨a+3£¬0£©£¬
¡ßÌÝÐÎEFGHµÄÃæ»ýS=
![](http://thumb.1010pic.com/pic5/latex/13.png)
£¨EH+FG£©•HG=
![](http://thumb.1010pic.com/pic5/latex/13.png)
[£¨
![](http://thumb.1010pic.com/pic5/latex/13.png)
a
2-
![](http://thumb.1010pic.com/pic5/latex/33.png)
a£©+
![](http://thumb.1010pic.com/pic5/latex/13.png)
£¨a+3£©
2-
![](http://thumb.1010pic.com/pic5/latex/33.png)
£¨a+3£©]¡Á3=
![](http://thumb.1010pic.com/pic5/latex/33.png)
a
2£¬
ÓÖ¡ß
![](http://thumb.1010pic.com/pic5/latex/13.png)
£¨a+3£©
2-
![](http://thumb.1010pic.com/pic5/latex/33.png)
£¨a+3£©-£¨
![](http://thumb.1010pic.com/pic5/latex/13.png)
a
2-
![](http://thumb.1010pic.com/pic5/latex/33.png)
a£©=3a£¬EF=
![](http://thumb.1010pic.com/pic5/latex/271997.png)
=3
![](http://thumb.1010pic.com/pic5/latex/24342.png)
£¬
¡à
![](http://thumb.1010pic.com/pic5/latex/407095.png)
=
![](http://thumb.1010pic.com/pic5/latex/429642.png)
-1£¬
¡àS=
![](http://thumb.1010pic.com/pic5/latex/7.png)
EF
2-
![](http://thumb.1010pic.com/pic5/latex/33.png)
£¬¼´SÊÇEF³¤¶ÈµÄ¶þ´Îº¯Êý£®
·ÖÎö£º£¨1£©ÓÉÅ×ÎïÏß¹ýÔµãO¼°Aµã£¨3£¬0£©£¬¸ù¾ÝÅ×ÎïÏߵĶԳÆÐÔ£¬ÓÉÖеã×ø±ê¹«Ê½£¬¼´¿ÉÇó³öÅ×ÎïÏߵĶԳÆÖáΪֱÏßx=
![](http://thumb.1010pic.com/pic5/latex/60645.png)
£¬¼´x=
![](http://thumb.1010pic.com/pic5/latex/33.png)
£»
£¨2£©ÏÈÓÉÅ×ÎïÏߵĶԳÆÖáΪֱÏßx=
![](http://thumb.1010pic.com/pic5/latex/33.png)
£¬ÉèÅ×ÎïÏߵĽâÎöʽΪ¶¥µãʽy=a£¨x-
![](http://thumb.1010pic.com/pic5/latex/33.png)
£©
2+k£¬Ôò¶¥µãBµÄ×ø±êΪ£¨
![](http://thumb.1010pic.com/pic5/latex/33.png)
£¬k£©£¬ÔÙ½«x=
![](http://thumb.1010pic.com/pic5/latex/190.png)
´úÈ룬Çó³öµãCµÄ×Ý×ø±êΪ9a+k£¬¸ù¾ÝMC=4.5£¬Çó³öa=
![](http://thumb.1010pic.com/pic5/latex/13.png)
£¬È»ºó½«Aµã×ø±ê£¨3£¬0£©´úÈëy=
![](http://thumb.1010pic.com/pic5/latex/13.png)
£¨x-
![](http://thumb.1010pic.com/pic5/latex/33.png)
£©
2+k£¬Çó³ök=-
![](http://thumb.1010pic.com/pic5/latex/4491.png)
£¬µÃµ½Å×ÎïÏߵĽâÎöʽΪy=
![](http://thumb.1010pic.com/pic5/latex/13.png)
£¨x-
![](http://thumb.1010pic.com/pic5/latex/33.png)
£©
2-
![](http://thumb.1010pic.com/pic5/latex/4491.png)
£¬¼´y=
![](http://thumb.1010pic.com/pic5/latex/13.png)
x
2-
![](http://thumb.1010pic.com/pic5/latex/33.png)
x£»
£¨3£©ÓÉÓÚO¡¢AÁ½µã¹ØÓÚÅ×ÎïÏߵĶԳÆÖá¶Ô³Æ£¬ËùÒÔÁ¬½ÓOC£¬½»Å×ÎïÏߵĶԳÆÖáÓÚµãD£¬Ôò¡÷ACDµÄÖܳ¤×îС£®ÏÈÔËÓôý¶¨ÏµÊý·¨Çó³öÖ±ÏßOCµÄ½âÎöʽ£¬ÔÙ½«x=
![](http://thumb.1010pic.com/pic5/latex/33.png)
´úÈ룬Çó³öyµÄÖµ£¬¼´¿ÉµÃµ½Dµã×ø±ê£»
£¨4£©ÏÈÓú¬aµÄ´úÊýʽ·Ö±ð±íʾE£¬H£¬F£¬GËĵãµÄ×ø±ê£¬µÃµ½EHÓëFGµÄ³¤¶È£¬ÔÙ¸ù¾ÝÌÝÐεÄÃæ»ý¹«Ê½Çó³öS=
![](http://thumb.1010pic.com/pic5/latex/33.png)
a
2£¬ÔÙÔËÓÃÁ½µãÖ®¼äµÄ¾àÀ빫ʽÇó³öEF=3
![](http://thumb.1010pic.com/pic5/latex/24342.png)
£¬Ôò
![](http://thumb.1010pic.com/pic5/latex/407095.png)
=
![](http://thumb.1010pic.com/pic5/latex/429642.png)
-1£¬ÕûÀíºóµÃ³öS=
![](http://thumb.1010pic.com/pic5/latex/7.png)
EF
2-
![](http://thumb.1010pic.com/pic5/latex/33.png)
£¬¼´SÊÇEF³¤¶ÈµÄ¶þ´Îº¯Êý£®
µãÆÀ£º±¾ÌâÊǶþ´Îº¯ÊýµÄ×ÛºÏÌâÐÍ£¬ÆäÖÐÉæ¼°µ½µÄ֪ʶµãÓÐÔËÓôý¶¨ÏµÊý·¨ÇóÕý±ÈÀýº¯ÊýÓë¶þ´Îº¯ÊýµÄ½âÎöʽ£¬¶þ´Îº¯ÊýµÄÐÔÖÊ£¬Æ½ÒÆ¡¢Öá¶Ô³ÆµÄÐÔÖÊ£¬ÌÝÐεÄÃæ»ý¡¢Á½µãÖ®¼äµÄ¾àÀ빫ʽ£¬×ÛºÏÐÔ½ÏÇ¿£¬ÄѶÈÊÊÖУ®¸ù¾ÝÅ×ÎïÏßµÄÐÔÖÊÔËÓôý¶¨ÏµÊý·¨Çó³ö¶þ´Îº¯ÊýµÄ½âÎöʽÊǽâÌâµÄ¹Ø¼ü£®