Suppose two particles A and B are moving along the x-axis. At time t particle A is located at the point on the x-axis with coordinate 5+7t. When t=0, B is at the origin. B's velocity is along the positive x-axis and is proportional to the distance between A and B with proportionality constant k. Derive the initial value problem that models B's position on the axis as a function of t (define the Differential Equation and Initial Condition).