(2) (b+c) le+arla+b) tabe = (bc+ab+c²+ac | (a + b) + a b c abcta²btat² + a²c + b²c+ab the tabetab = (b+c) a² + (b²+3 bc+c²) a + b c lb + c ) = \\b+c)α} + { (b+c)²+be} a+belb+c) = (b+c) { a² + (btct be la+be (b+c)} (b+c)(a+b+c) (a+bc)