1 ) ( b - 3 ) ^ 3 - 1 = ( b - 3 ) ^ 3 - 1 ^ 3 = ( b - 3 - 1 ) * ( ( b - 3 ) ^ 2 + 1 * ( b - 3 ) + 1 ^ 2 ) = ( b - 4 ) * ( ( b - 3 ) ^ 2 + 1 * ( b - 3 ) + 1 ^ 2 ) = ( b - 4 ) * ( ( b - 3 ) ^ 2 + ( b - 3 ) + 1 ) = ( b - 4 ) * ( b ^ 2 - 6 * b + 9 + b - 3 + 1 ) = ( b - 4 ) * ( b ^ 2 - 5 * b + 7 ); 2 ) ( a + b ) ^ 3 - ( a - b ) ^ 3 = ( a + b - ( a - b ) ) * ( ( a + b ) ^ 2 + ( a + b ) * ( a - b ) + ( a - b ) ^ 2 ) = ( a + b - a + b ) ) * ( a ^ 2 + 2 * a * b + b ^ 2 + a^ 2 - b ^ 2 + a ^ 2 - 2 * a * b + b ^ 2 ) = ( b + b ) ) * ( a ^ 2 + b ^ 2 + a^ 2 + a ^ 2 ) = 2 * b * ( 3 * a ^ 2 + b ^ 2 ).