Question

If the equation $(m-n)x^2+(n-1)x+1-m=0$ has equal roots, then l, m and $n$ satisfy

• A. 2l = m + n
• B. 2m = n + l
• C. m = n + l
• D. l = m + n

Answer 1

Answer: (B)

As sum of coefficients is zero, hence one root is 1
and other root is $\frac{l-m}{m-n}$.
Since roots are equal,
$\therefore \frac{1-m}{m-n}=1$
$\Rightarrow 2m=n+1$.