已知：a + b = 3； a b = -2则(a+1)(b+1) = ab + a + b + 1 = ab + (a + b) + 1 = -2 + 3 + 1 = 2 补充：1/a + 1/b = (a+b) / (ab) = 3 / (-2) = -3/2a² + b² = (a+b)² - 2ab = 3² - 2(-2) = 13...