题目

--- I know how much it will take you to buy a ticket for sporting events of the 2008 Olympic Games. --- How did you know it? --- It was in the website www. tickets. Beijing 2008.cn        you can buy the tickets for the opening ceremony for the Beijing 2008 Olympic Games on August 8         I found the full details about tickets prices for them. A．where; that      B．which; that       C．that; which       D．where; which（1）实验与观察：（用“＞”、“=”或“＜”填空）当x=-5时，代数式x2-2x+2 1；当x=1时，代数式x2-2x+2 1；…（2）归纳与证明：换几个数再试试，你发现了什么？请写出来并证明它是正确的；（3）拓展与应用：求代数式a2+b2-6a-8b+30的最小值．