Cinderella（灰姑娘）was a p____ but poor girl. Her stepmother(继母) treated her very badly. She made her do all of the h____. day and night. She didn't tell her father about the sad thing because she loved her father and didn't want him to w____ about her.

    One day, a prince (王子) in the country i____ all the young girls to his birthday party. But she only had dirty and old c____ , so she cried and cried. Suddenly a fairy（仙女）came and helped her go to the party. However, the fairy told her that she had to come back b____ twelve o'clock. During the dancing party, she and the prince danced together very well. 

    When the bell rang at 12 o'clock, she went b____ home very quickly but l____ one glass shoe in the palace. Then the prince took the glass shoe and asked from door to door around the country to l____ for the girl who wore it. At last, he found Cinderella and married(娶) her. They lived h____ ever after.

（Ⅰ）求证：数列{a_n+b_n}和{a_n﹣b_n}都是等比数列，并求数列{a_n}的通项公式；

（Ⅱ）若c_n=（a_n﹣3ⁿ）log₃a_n﹣（﹣1）ⁿ，求数列{c_n}的前n项和T_n．

梧州是一座有着2 100多年历史的岭南名城，曾是广西第一大城市，有着“百年商埠”“小香港”之美誉。新中国成立后，南宁、柳州、桂林的发展相继超过梧州。下图示意广西部分主要城市分布(国家测绘局2008年资料) ，据此回答下面小题。