Question

19£®¼Îä¿Í¬Ñ§¼ÒµÄÒûË®»úÖÐÔ­ÓÐË®µÄζÈΪ20¡æ£¬Æ乤×÷¹ý³ÌÈçͼËùʾ£¬ÔÚÒ»¸öÓÉ20¡æ¼ÓÈȵ½100¡æÔÙ½µÎµ½20¡æµÄ¹ý³ÌÖУ¬Ë®Î¼Ç×÷y£¨¡æ£©£¬´Ó¿ªÊ¼¼ÓÈÈÆðʱ¼ä±ä»¯ÁËx£¨·ÖÖÓ£©£¬¼ÓÈȹý³ÌÖУ¬yÓëxÂú×ãÒ»´Îº¯Êý¹Øϵ£¬Ë®ÎÂϽµ¹ý³ÌÖУ¬yÓëx³É·´±ÈÀý£¬µ±x=20ʱ£¬y=40£®
£¨1£©Ð´³öÒûË®»úˮεÄϽµ¹ý³ÌÖÐyÓëxµÄº¯Êý¹Øϵ£¬²¢Çó³öxΪºÎֵʱ£¬y=100£»
£¨2£©Çó¼ÓÈȹý³ÌÖÐyÓëxÖ®¼äµÄº¯Êý¹Øϵ£»
£¨3£©Çóµ±xΪºÎֵʱ£¬y=80£®
ÎÊÌâ½â¾ö
Èô¼Îä¿Í¬Ñ§ÉÏÎç°Ëµã½«ÒûË®»úͨµç¿ª»úºó¼´Íâ³öÉ¢²½£¬Ô¤¼Æ¾ÅµãÇ°»Øµ½¼ÒÖУ¬Èô¼Îä¿ÏëºÈµ½²»µÍÓÚ50¡æµÄË®£¬Ö±½Óд³öÍâ³öʱ¼äm£¨·ÖÖÓ£©µÄÈ¡Öµ·¶Î§£®

Answer 1

·ÖÎö £¨1£©¸ù¾Ý´ý¶¨ÏµÊý·¨¿ÉÇóÒûË®»úˮεÄϽµ¹ý³ÌÖÐyÓëxµÄº¯Êý¹Øϵʽ£¬ÔÙÇó³öy=100ʱxµÄÖµ¼´¿ÉÇó½â£»
£¨2£©¸ù¾Ý´ý¶¨ÏµÊý·¨¿ÉÇó¼ÓÈȹý³ÌÖÐyÓëxÖ®¼äµÄº¯Êý¹Øϵ£»
£¨3£©·ÖÁ½ÖÖÇé¿ö£º¼ÓÈȹý³ÌÖУ»½µÎ¹ý³ÌÖУ»y=80ʱxµÄÖµ¼´¿ÉÇó½â£»
ÎÊÌâ½â¾ö£º¸ù¾ÝÒ»´Îº¯ÊýºÍ·´±ÈÀýº¯ÊýµÄÔö¼õÐÔ¼´¿ÉÇó½â£®

½â´ð ½â£º£¨1£©ÔÚË®ÎÂϽµ¹ý³ÌÖУ¬ÉèË®ÎÂy£¨¡æ£©Ó뿪»úʱ¼äx£¨·Ö£©µÄº¯Êý¹ØϵʽΪ£ºy=$\frac{m}{x}$£¬
ÒÀ¾ÝÌâÒ⣬µÃ£º100=$\frac{m}{8}$£¬
¼´m=800£¬
¹Êy=$\frac{800}{x}$£¬
µ±y=100ʱ£¬100=$\frac{800}{x}$£¬
½âµÃ£ºx=8£»

£¨2£©ÉèË®ÎÂy£¨¡æ£©Ó뿪»úʱ¼äx£¨·Ö£©µÄº¯Êý¹ØϵΪ£ºy=kx+b£¬
ÒÀ¾ÝÌâÒ⣬µÃ$\left\{\begin{array}{l}{8k+b=100}\\{b=20}\end{array}\right.$£¬
½âµÃ£º$\left\{\begin{array}{l}{k=10}\\{b=20}\end{array}\right.$£®
¹Ê´Ëº¯Êý½âÎöʽΪ£ºy=10x+20£»

£¨3£©µ±y=80ʱ£º
¼ÓÈȹý³ÌÖУº10x+20=80£¬½âµÃx=6£»
½µÎ¹ý³ÌÖУº$\frac{800}{x}$=80£¬½âµÃx=10£»
×ÛÉÏËùÊö£¬x=6»ò10ʱ£¬y=80£»       
ÎÊÌâ½â¾ö£ºÍâ³öʱ¼äm£¨·ÖÖÓ£©µÄÈ¡Öµ·¶Î§Îª3¡Üm¡Ü16»ò43¡Üm¡Ü56£®

µãÆÀ ´ËÌ⿼²éÁËÒ»´Îº¯ÊýºÍ·´±ÈÀýº¯ÊýµÄÓ¦Óã¬ÏÖʵÉú»îÖдæÔÚ´óÁ¿Ò»´Îº¯ÊýºÍ³É·´±ÈÀýº¯ÊýµÄÁ½¸ö±äÁ¿£¬½â´ð¸ÃÀàÎÊÌâµÄ¹Ø¼üÊÇÈ·¶¨Á½¸ö±äÁ¿Ö®¼äµÄº¯Êý¹Øϵ£¬È»ºóÀûÓôý¶¨ÏµÊý·¨Çó³öËüÃǵĹØϵʽ£®