材料：在这个激动人心的时刻，首都北京30万人聚集在天安门广场上，***向全世界庄严宣布：“中华人民共和国中央人民政府今天成立了！”接着，***主席按动电钮，五星红旗在雄壮的国歌声中冉冉升起………广场上响起暴风雨般的欢呼声。

下列算式中，计算结果为x²－3x－28的是（    ）

   Mr. King works very long hours every day. He usually gets up at 5:30. He brushes his teeth quickly and goes to his workplace (工作地点). Then he runs with some kids. After that he takes a shower. He eats his breakfast at 7:00. His work starts at 8:10. He is good at math and many boys and girls learn math from him. All the kids like him very much. He often talks or plays games with the kids. He usually goes to bed after 22:00. He is often very tired but he likes his job and loves the kids. He doesn’t work on weekends. Mr. King likes reading at home on weekends. Sometimes some kids’ parents come to his home to talk about their kids. When Monday comes, Mr. King gets busy again

如图，将正偶数按照图中所示的规律排列下去，若用有序实数对（a，b）表示第a行的第b个数．如（3，2）表示偶数10．

（1）图中（8，4）的位置表示的数是____ ，偶数42对应的有序实数对是____

（2）第n行的最后一个数用含n的代数式表示为____ ，并简要说明理由．