Consider the two sets: A = m ∈ R : both the roots of x 2 - ( m + 1 ) x + m + 4 = 0 are real and B = [ - 3 , 5 ) Which of the following is not true?

Step-by-step solution

Since both roots are real m + 1 2 - 4 m + 4 ≥ 0 ⇒ m 2 - 2 m - 15 ≥ 0 ⇒ m - 5 m + 3 ≥ 0 ⇒ m ∈ ( - ∞ , - 3 ] ∪ [ 5 , ∞ ) ⇒ A = ( - ∞ , - 3 ] ∪ [ 5 , ∞ ) A - B = - ∞ , - 3 ∪ [ 5 , ∞ ) A ∩ B = - 3 B - A = - 3 , 5 A ∪ B = R