Question 118532
if something is a "root," it means it is a value for x which satisfies the equation. So plug the root in for x ans solve for k:
{{{x^2+kx+7=0}}}
{{{(3+sqrt(2))^2+k(3+sqrt(2))+7=0}}}
{{{9+6sqrt(2)+2+k(3+sqrt(2))+7=0}}}
{{{9+8.485+2+k(4.414)+7=0}}}
{{{k(4.414)+26.485=0}}}
{{{k(4.414)=-26.485}}}
{{{highlight(k=-6)}}}