Question

If the equation $4x^2+x(p+1)+1=0$ has exactly two equal roots, then one of the values of $p$ is

• A. $5$
• B. $-3$
• C. $0$
• D. $3$

Answer 1

The correct option is D $3$

For the equation $4x^2+x(p+1)+1=0$ to have two equal roots, the condition is Discriminant $=0$
$b^2-4ac=0$
$(p+1{)}^2-4\times 4\times 1=0$
$p^2+2p+1-16=0$
$p^2+2p-15=0$
$(p+5)(p-3)=0$
$\therefore p=-5$ or $p=3$
Hence, one of the values of $p$ is $3$.

Option D is correct.