Question

Total number of integral values of a so that

x² –(a+1) x+a–1 = 0 has integral roots is equal to –

• A. 1
• B. 2
• C. 3
• D. 4

Answer 1

Answer: (A)

1

Answer 2

x² – ax – x + a = 1 ⇒ (x – a) (x – 1) = 1

⇒ x– 1 = 1or –1 & x – a = 1 or – 1

⇒ x = 2 ⇒ a = 1

x = 0 ⇒ a = 1 ⇒ only one value