Algebra Formula

                              [1]       ( a + b )²  =  a²  + 2ab + b² ,

                              [2]       ( a – b )²  =  a² – 2ab + b² ,

                              [3]       ( a + b ) ( a – b ) = a²  –  b²,

                              [4]       ( a + b )³  =  a³  + 3a² b + 3ab²  + b³ ,

                              [5]       ( a – b )³  =  a ³  – 3a² b + 3ab²  – b³ ,

                              [6]       ( a + b )( a²  – ab + b² ) =  a³ + b³ ,

                              [7]       ( a – b )( a ²  + ab + b² ) =  a³ – b³ .