ÌâÄ¿ÄÚÈÝ
19£®·ûºÅ$|\begin{array}{l}{a}&{b}\\{c}&{d}\end{array}|$½Ð×ö¶þ½×ÐÐÁÐʽ£¬¹æ¶¨ËüµÄÔËËã·¨ÔòΪ$|\begin{array}{l}{a}&{b}\\{c}&{d}\end{array}|$=ad-bc£¬ÀýÈç$|\begin{array}{l}{1}&{2}\\{3}&{4}\end{array}|$=1¡Á4-2¡Á3=-2£®ÄÇô£¬¸ù¾ÝÔĶÁ²ÄÁÏ£¬»¯¼ò$|\begin{array}{l}{a+2}&{a+3}\\{a-2}&{a+3}\end{array}|$=4a+12£®·ÖÎö ÀûÓÃÌâÖеÄж¨Ò弯Ëã¼´¿ÉµÃµ½½á¹û£®
½â´ð ½â£ºÔʽ=£¨a+2£©£¨a+3£©-£¨a-2£©£¨a+3£©
=a2+5a+6-a2-a+6
=4a+12£¬
¹Ê´ð°¸Îª£º4a+12£®
µãÆÀ ´ËÌ⿼²éÁËÕûʽµÄ¼Ó¼õ£¬ÊìÁ·ÕÆÎÕÔËËã·¨ÔòÊǽⱾÌâµÄ¹Ø¼ü£®
Á·Ï°²áϵÁдð°¸
Ïà¹ØÌâÄ¿
4£®2015ÄêÎÒ¹ú´óѧÉú±ÏÒµÈËÊý½«´ïµ½7 490 000ÈË£¬Õâ¸öÊý¾ÝÓÿÆÑ§¼ÇÊý·¨±íʾΪ£¨¡¡¡¡£©
| A£® | 7.49¡Á107 | B£® | 7.49¡Á106 | C£® | 74.9¡Á105 | D£® | 0.749¡Á107 |
5£®ÏÂÁк¯Êý½âÎöʽÖУ¬Ò»¶¨Îª¶þ´Îº¯ÊýµÄÊÇ£¨¡¡¡¡£©
| A£® | y=3x-1 | B£® | y=ax2+bx+c | C£® | s=2t2-2t+1 | D£® | y=x2+$\frac{1}{x}$ |
14£®ÏÂÁÐÊǶþÔªÒ»´Î·½³ÌµÄÊÇ£¨¡¡¡¡£©
| A£® | 3x+4=9 | B£® | $\frac{1}{x}+\frac{2}{3y}=2$ | C£® | x2+y=0 | D£® | 6x+1=y |
4£®·½³Ìx+y=6µÄ½âÓУ¨¡¡¡¡£©
| A£® | 0¸ö | B£® | 2¸ö | C£® | 3¸ö | D£® | ÎÞÊý¸ö |