Question 1068660
Use the distance formula to find the distance from the origin,
{{{D^2=(3sqrt(5)-0)^2+((d+3)-0)^2}}}
{{{D^2=45+(d+3)^2}}}
But you know that {{{D=3d}}}
{{{9d^2=45+d^2+6d+9}}}
{{{8d^2-6d-54=0}}}
{{{4d^2-3d-27=0}}}
{{{(4d+9)(d-3)=0}}}
Only a positive d makes sense in this problem,
{{{d-3=0}}}
{{{d=3}}}