Question

The number of integral values of a for which the quadratic equation (x+a)(x+1991)+1 = 0 has integral roots are

• A. 3
• B. 0
• C. 1
• D. 2

Answer 1

The correct option is D

2

(x+a)(x+1991)+1 = 0

$\Rightarrow$ (x+a)(x+1991) = -1

$\Rightarrow$ (x+a) = 1 and x+1991 = -1

$\Rightarrow$a = 1993 or x+a = -1 and x+1991 = 1

$\Rightarrow$ a= 1993 or a = 1989