# If the eqn., $x^2-m(2x-8)-15=0$ has equal roots, then $m=?$

$\begin{array}{1 1}(A) 3\;or\;5 \\ (B) -3\;or \;5 \\ (C) 3\;or\;-5 \\(D) -3\;or\;-5 \end{array}$

Given eqn., is $x^2-2mx+(8m-15)=0$
It has equal roots.
$\Rightarrow\:4m^2-4(8m-15)=0$
$\Rightarrow\:m^2-8m+15=0$
$\Rightarrow\:m=3\:\:or\:\:5$