Question

If the roots of the equation $x^2+a^2=8x+6a$ are real, then

• A. $aϵ(2,8)$
• B. $aϵ[2,8]$
• C. $aϵ(-2,8)$
• D. $aϵ[-2,8]$

Answer 1

The correct option is D $aϵ[-2,8]$

Since, its roots are real
$\therefore 64-4(a^2-6a)\ge 0$
$\Rightarrow -2\le a\le 8$
$\Rightarrow aϵ[-2,8]$