15£®ÎÒÊÐij±ö¹ÝÓµÓпͷ¿100¼ä£¬¾­ÓªÖз¢ÏÖ£ºÃ¿ÌìÈëסµÄ¿Í·¿Êýy£¨¼ä£©Óë·¿¼Ûx£¨Ôª£©£¨180¡Üx¡Ü300£©Âú×ãÒ»´Îº¯Êý¹Øϵ£¬²¿·Ö¶ÔÓ¦ÖµÈç±í£º
x£¨Ôª£©180210260300
y£¨¼ä£©100856040
£¨1£©ÇóyÓëxÖ®¼äµÄº¯Êý±í´ïʽ£»
£¨2£©ÒÑ֪ÿ¼äÈëסµÄ¿Í·¿£¬±ö¹ÝÿÈÕÐèÖ§³ö¸÷ÖÖ·ÑÓÃ80Ôª£»Ã¿ÈÕ¿ÕÖõĿͷ¿£¬±ö¹ÝÿÈÕÐèÖ§³ö40Ôª£¬µ±·¿¼ÛΪ¶àÉÙԪʱ£¬±ö¹Ýµ±ÈÕÀûÈó×î´ó£¿Çó³ö×î´óÖµ£®£¨±ö¹Ýµ±ÈÕÀûÈó=µ±ÈÕ·¿·ÑÊÕÈë-µ±ÈÕÖ§³ö£©

·ÖÎö £¨1£©ÉèÒ»´Îº¯Êý±í´ïʽΪy=kx+b£¨k¡Ù0£©£¬ÓɵãµÄ×ø±ê£¨180£¬100£©¡¢£¨260£¬60£©ÀûÓôý¶¨ÏµÊý·¨¼´¿ÉÇó³ö¸ÃÒ»´Îº¯Êý±í´ïʽ£»
£¨2£©Éè·¿¼ÛΪxÔª£¨180¡Üx¡Ü300£©Ê±£¬±ö¹Ýµ±ÈÕÀûÈóΪwÔª£¬ÒÀ¾Ý¡°±ö¹Ýµ±ÈÕÀûÈó=µ±ÈÕ·¿·ÑÊÕÈë-µ±ÈÕÖ§³ö¡±¼´¿ÉµÃ³öw¹ØÓÚxµÄ¶þ´Îº¯Êý¹Øʽ£¬¸ù¾Ý¶þ´Îº¯ÊýµÄÐÔÖʼ´¿É½â¾ö×îÖµÎÊÌ⣮

½â´ð ½â£º£¨1£©ÉèÒ»´Îº¯Êý±í´ïʽΪy=kx+b£¨k¡Ù0£©£¬ÒÀÌâÒâµÃ£º
$\left\{\begin{array}{l}{180k+b=100}\\{260k+b=60}\end{array}\right.$£¬½âµÃ£º$\left\{\begin{array}{l}{k=-\frac{1}{2}}\\{b=190}\end{array}\right.$£®
¡àyÓëxÖ®¼äµÄº¯Êý±í´ïʽΪy=-$\frac{1}{2}$x+190£¨180¡Üx¡Ü300£©£®
£¨2£©Éè·¿¼ÛΪxÔª£¨180¡Üx¡Ü300£©Ê±£¬±ö¹Ýµ±ÈÕÀûÈóΪwÔª£¬ÒÀÌâÒâµÃ£º
w=£¨-$\frac{1}{2}$x+190£©£¨x-80£©-40¡Á[100-£¨-$\frac{1}{2}$x+190£©]=-$\frac{1}{2}$x2+210x-12200=-$\frac{1}{2}$£¨x-210£©2+9850£¬
¡àµ±x=210ʱ£¬wÈ¡×î´óÖµ£¬×î´óֵΪ9850£®
´ð£ºµ±·¿¼ÛΪ210Ԫʱ£¬±ö¹Ýµ±ÈÕÀûÈó×î´ó£¬×î´óÀûÈóΪ8950Ôª£®

µãÆÀ ±¾Ì⿼²éÁ˶þ´Îº¯ÊýµÄÓ¦Óᢴý¶¨ÏµÊý·¨Çóº¯Êý½âÎöʽÒÔ¼°¶þ´Îº¯ÊýµÄÐÔÖÊ£¬½âÌâµÄ¹Ø¼üÊÇ£º£¨1£©ÀûÓôý¶¨ÏµÊý·¨Çó³öº¯Êý½âÎöʽ£»£¨2£©¸ù¾ÝÊýÁ¿¹ØϵÕÒ³öw¹ØÓÚxµÄº¯Êý¹Øϵʽ£®±¾ÌâÊôÓÚÖеµÌ⣬ÄѶȲ»´ó£¬µ«ÔËËãÊý¾Ý½Ï´ó£¬½â¾ö¸ÃÌâÐÍÌâĿʱ£¬¸ù¾ÝµãµÄ×ø±êÀûÓôý¶¨ÏµÊý·¨Çó³öº¯Êý½âÎöʽÊǹؼü£®

Á·Ï°²áϵÁдð°¸
Ïà¹ØÏ°Ìâ

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£º½â´ðÌâ

5£®£¨1£©½â·½³Ì£º$\frac{x-1}{x}$+$\frac{3x}{x-1}$=4
£¨2£©½â²»µÈʽ×é$\left\{\begin{array}{l}{2£¨x+8£©¡Ü10-4£¨x-3£©}\\{\frac{x+1}{2}-\frac{6x+7}{3}£¼1}\end{array}\right.$£¬²¢°ÑËüÃǵĽ⼯ÔÚÊýÖáÉϱíʾ³öÀ´£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£ºÌî¿ÕÌâ

6£®Èçͼ£¬Õý·½ÐÎABCDµÄÃæ»ýΪ2$\sqrt{5}$cm2£¬¶Ô½ÇÏß½»ÓÚµãO1£¬ÒÔAB¡¢AO1ΪÁÚ±ß×öƽÐÐËıßÐÎAO1C1B£¬¶Ô½ÇÏß½»ÓÚµãO2£¬ÒÔAB¡¢AO2ΪÁÚ±ß×öƽÐÐËıßÐÎAO2C2B£¬¡­£¬ÒÔ´ËÀàÍÆ£¬ÔòƽÐÐËıßÐÎAO6C6BµÄÃæ»ýΪ$\frac{\sqrt{5}}{{2}^{5}}$cm2£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£º½â´ðÌâ

3£®Èçͼ1£¬BCÊÇ¡ÑOµÄÖ±¾¶£¬AÊÇ¡ÑOÉÏÒ»µã£¬¹ýµãB×÷¨’OµÄÇÐÏߣ¬ÓëCAµÄÑÓ³¤ÏßÏཻÓÚµãE£¬FÊÇBEµÄÖе㣬ÑÓ³¤AFÓëCBµÄÑÓ³¤ÏßÏཻÓÚµãP£®
£¨1£©ÇóÖ¤£ºPAÊÇ¡ÑOµÄÇÐÏߣ»
£¨2£©Èçͼ2£¬ÈôAD¡ÍBCÓÚµãD£¬Á¬½ÓCFÓëADÏཻÓÚµãG£¬ÇóÖ¤£ºAG=GD£»
£¨3£©ÔÚ£¨2£©µÄÌõ¼þÏ£¬ÈôFG=BF£¬ÇÒ¡ÑOµÄ°ë¾¶³¤Îª3$\sqrt{2}$£¬ÇóBDµÄ³¤¶È£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£ºÌî¿ÕÌâ

10£®Èô$\sqrt{a-2}$+|b+3|=0£¬Ôò£¨a+b£©2017µÄÖµÊÇ-1£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£º½â´ðÌâ

20£®ÏÈ»¯¼ò£¬ÔÙÇóÖµ£º£¨x-1-$\frac{3}{x+1}$£©¡Â$\frac{{x}^{2}-4x+4}{x+1}$£¬ÆäÖÐx=-4£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£º½â´ðÌâ

7£®Ä³Ð£×¼±¸×é֯ʦÉú¹²80ÈË£¬´ÓÎÂÖݳË×ø¶¯³µÇ°ÍùÑãÂäɽ²Î¼ÓÏÄÁîÓª»î¶¯£¬½Ìʦ°´³ÉÈËƱ¼Û¹ºÂò£¬Ñ§Éú°´Ñ§ÉúƱ¼Û¹ºÂò£¬¶¯³µÆ±¼Û¸ñÈç±íËùʾ£º
ÔËÐÐÇø¼ä³ÉÈËƱ¼Û£¨Ôª/ÕÅ£©Ñ§ÉúƱ¼Û£¨Ôª/ÕÅ£©
³ö·¢Õ¾ÖÕµãÕ¾Ò»µÈ×ù¶þµÈ×ù¶þµÈ×ù
ÎÂÖÝÄÏÑãÂäɽ262216
ÈôʦÉú¾ù¹ºÂò¶þµÈ×ùƱ£¬Ôò¹²Ðè1370Ôª£®
£¨1£©²Î¼Ó»î¶¯µÄ½ÌʦºÍѧÉú¸÷ÓжàÉÙÈË£»
£¨2£©ÓÉÓÚ²¿·Ö½ÌʦÐèÌáÔçÇ°Íù×ö×¼±¸¹¤×÷£¬Õⲿ·Ö½Ìʦ¾ù¹ºÂòÒ»µÈ×ùƱ£¬¶øºóÐøÇ°ÍùµÄ½ÌʦºÍѧÉú¾ù¹ºÂò¶þµÈ×ùƱ£®ÉèÌáÔçÇ°ÍùµÄ½ÌʦÓÐxÈË£¬¹ºÂòÒ»¡¢¶þµÈ×ùƱȫ²¿·ÑÓÃΪyÔª£®Çóy¹ØÓÚxµÄº¯Êý¹Øϵʽ£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£º½â´ðÌâ

4£®ÏÈ»¯¼ò£¬ÔÙÇóÖµ£ºm£¨m-2£©-£¨m-1£©2+m£¬ÆäÖÐm=-$\frac{1}{3}$£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£ºÑ¡ÔñÌâ

5£®ÈôÅ×ÎïÏßy=x2-4x+2-t£¨tΪʵÊý£©ÔÚ0£¼x£¼$\frac{5}{2}$µÄ·¶Î§ÄÚÓëxÖáÓй«¹²µã£¬ÔòtµÄÈ¡Öµ·¶Î§Îª£¨¡¡¡¡£©
A£®-2£¼t£¼2B£®-2¡Üt£¼2C£®-$\frac{7}{4}$£¼t£¼2D£®t¡Ý-2

²é¿´´ð°¸ºÍ½âÎö>>

ͬ²½Á·Ï°²á´ð°¸