Question 1046576
So assume the plane is at ({{{x}}},{{{y}}}).
The distance from A to the plane is {{{D[A]=sqrt((x-0)^2+(y-0)^2)=sqrt(x^2+y^2)}}}.
The distance from B to the plane is {{{D[B]=sqrt((x-0)^2+(y-5)^2)=sqrt(x^2+(y-5)^2)}}}.
You also know that,
{{{D[B]=D[A]+3}}}
{{{sqrt(x^2+(y-5)^2)=sqrt(x^2+y^2)+3}}}