ÌâÄ¿ÄÚÈÝ
3£®ÔĶÁ²ÄÁÏ£º¶ÔÓÚÈκÎÊý£¬ÎÒÃǹ涨·ûºÅ$|\begin{array}{l}{a}&{b}\\{c}&{d}\end{array}|$µÄÒâÒåÊÇ$|\begin{array}{l}{a}&{b}\\{c}&{d}\end{array}|$=ad-bc£®ÀýÈ磺$|\begin{array}{l}{1}&{2}\\{3}&{4}\end{array}|$=1¡Á4-2¡Á3=-2£®
£¨1£©°´ÕÕÕâ¸ö¹æ¶¨£¬ÇëÄã¼ÆËã$|\begin{array}{l}{1}&{-2}\\{3}&{-1}\end{array}|$|µÄÖµ£»
£¨2£©°´ÕÕÕâ¸ö¹æ¶¨£¬ÇëÄã¼ÆËã £¨x-2£©2+£¨y+$\frac{1}{5}$£©2=0ʱ£¬$|\begin{array}{l}{-3{x}^{2}+y}&{{x}^{2}+y}\\{3}&{-2}\end{array}|$Öµ£®
·ÖÎö £¨1£©¸ù¾ÝÌâÒâ¿ÉÖªÁгöʽ×ÓÇó½â£®
£¨2£©ÏÈ»¯¼òËùÇóµÄʽ×Ó£¬È»ºó½«xÓëyµÄÖµ´úÈë¼´¿ÉÇó³ö´ð°¸£®
½â´ð ½â£º£¨1£©ÓÉÌâÒâ¿ÉÖª£º$|\begin{array}{l}{1}&{-2}\\{3}&{-1}\end{array}|$=1¡Á£¨-1£©-£¨-2£©¡Á3=-1+6=5£»
£¨2£©¡ß£¨x-2£©2+£¨y+$\frac{1}{5}$£©2=0£¬
¡àx=2£¬y=-$\frac{1}{5}$£¬
¡à$|\begin{array}{l}{-3{x}^{2}+y}&{{x}^{2}+y}\\{3}&{-2}\end{array}|$=-2£¨-3x2+y£©-3£¨x2+y£©
=6x2-2y-3x2-3y
=3x2-5y
=3¡Á4-5¡Á£¨-$\frac{1}{5}$£©
=12+1
=13
µãÆÀ ±¾Ì⿼²éж¨ÒåÐÍÔËËã£¬Éæ¼°ÕûʽµÄ¼Ó¼õ£¬ÓÐÀíÊý»ìºÏÔËËãµÄ£¬ÌâÄ¿½ÏΪ×ۺϣ®
Á·Ï°²áϵÁдð°¸
Ïà¹ØÌâÄ¿
18£®ÒÑÖªxy¡Ù0£¬ÇÒxy=y-x£¬Ôò·Öʽ$\frac{1}{x}$-$\frac{1}{y}$µÄֵΪ£¨¡¡¡¡£©
| A£® | xy | B£® | y-x | C£® | 1 | D£® | -1 |
12£®»ð²ñ°ô°´Í¼ÖÐËùʾµÄ·½·¨´îͼÐΣ®

£¨1£©ÌîдÏÂ±í£º
£¨2£©µ±Èý½ÇÐεĸöÊýÊÇ15ʱ£¬»ð²ñ°ôµÄ¸ùÊýÓжàÉÙ£¿
£¨3£©µ±Èý½ÇÐεĸöÊýÊÇnʱ£¬»ð²ñ°ôµÄ¸ùÊýÈçºÎ±íʾ£¿
£¨1£©ÌîдÏÂ±í£º
| Èý½ÇÐεĸöÊý | 1 | 2 | 3 | 4 | ¡ |
| »ð²ñ°ôµÄ¸ùÊý | 3 | 5 | 7 | 9 | ¡ |
£¨3£©µ±Èý½ÇÐεĸöÊýÊÇnʱ£¬»ð²ñ°ôµÄ¸ùÊýÈçºÎ±íʾ£¿