Scene 1 (0s)
( a+b ) 2 = a 2 + 2ab + b 2.
Scene 2 (6s)
(a-b) 2 = a 2 - 2ab + b 2.
Scene 3 (12s)
(a + b)( a- b) = a 2 – b 2.
Scene 4 (19s)
( x+a )( x+b ) =x 2 + (a + b)x + ab.
Scene 5 (25s)
(a + b) 3 =a 3 + 3a 2 b +3ab 2 + b 3.
Scene 6 (32s)
( a+b ) 3 = a 3 + 3a 2 b + 3ab 2 +b 2.
Scene 7 (39s)
( x+a )( x+b )( x+b )=x 3 +( a+b+c )x 2 +( ab+bc+ca ) x+abc.