Number of integral values of `a` for which quadratic equation `(a - 1)x^2+ (4a + 1) x - 6 = 0` have both roots integer, is

The least integral value of 'a' for which the equation x^2+2(a - 1)x + (2a + 1) = 0 has both the roots positive, is

Find all the integral values of a for which the quadratic equation (x - a) (x - 10) + 1 = 0 has integral roots.

The number of integral values of 'a' for which the quadratic equation x^(2)+(a+19)x+19a+1=0 has integral roots,are

Number of possible value(s) of integer 'a' for which the quadratic equation x^(2) + ax + 16 = 0 has integral roots, is

Number of possible value(s) of integer 'a' for which the quadratic equation x^(2) + ax + 16 = 0 has integral roots, is

Number of integral values of a for which the equation x^2-(a+1)x+a-1=0 , has integral roots, is equal to -

Number of integral values of a for which the equation x^(2)-(a+1)x+a-1=0, has integral roots,is equal to -

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