Question 765365
Exercise is for using the discriminant.  


{{{((3k)^2-4(k-2)(3k+6))}}}, the discriminant.


{{{(9k^2-4(3k^2-12))}}}
{{{(9k^2-12k^2+48)}}}
{{{(-3k^2+48)}}}


You want the discriminant to be 0 to make f(x) have only one solution.  This solution will be real.


{{{-3k^2+48=0}}}
{{{3k^2=48}}}
{{{k^2=24*2/3=8*2=16}}}
{{{highlight(k=-4)}}} OR {{{highlight(k=4)}}}