Recorda les IDENTITATS NOTABLES! Opera i simplifica: * ( a + b ) 2 * ( a - b) 2 * ( a + b ) ( a - b) = = a2 a2 + b2 + b2 = a2 + - - 2ab 2ab b2 ( 2 + 3 ) · ( 6 - 1 ) = + ( 5 - 6 ) · ( 5 + 6 ) = - ( 2 5 - 6 )2 = - ( 2 - 1 ) · ( 2 + 1 ) · 3 = 3 3 - 2 - 3 2 + 2 = + 7 7 - + 5 5 - 7 7 - + 5 5 = - 1 2 + 2 1 - 1 + 2 1 + 1 = - |