(1)
第一行分别为:1,4,9,1
第二行分别为:1,4,9,1
(2)
规律:x²-2xy+y²=(x-y)²
2009²-2×2009×2000+2000²
=(2009-2000)²
=9²
=81
(3)
﹙n﹢2﹜²-2﹙n+2﹚﹙n-2﹜+﹛n-2﹚²
=[﹙n﹢2)-(n-2)]²
=(n+2-n+2)²
=4²
=16
(1)
第一行分别为:1,4,9,1
第二行分别为:1,4,9,1
(2)
规律:x²-2xy+y²=(x-y)²
2009²-2×2009×2000+2000²
=(2009-2000)²
=9²
=81
(3)
﹙n﹢2﹜²-2﹙n+2﹚﹙n-2﹜+﹛n-2﹚²
=[﹙n﹢2)-(n-2)]²
=(n+2-n+2)²
=4²
=16