Question

Number of positive integral values of $b$ for which both roots of the quadratic equation $x^2+bx-16=0$ are integers, is

• A. $3$
• B. $4$
• C. $5$
• D. $6$

Answer 1

The correct option is C $5$

$16$
$=2^4$
Hence , the factors are
$2,4,8,16,1$
Hence,
$b=-4+4=0$
$b=-2+8=6$
$b=-8+2=-6$
$b=-1+16=-15$
$b=1-16=15$
Hence, in total there are $5$ integral values of b out of which three are positive integral values.