solving the given equations A(0,3) and is the midpoint
using midpoint formula we get C(4,5)
given lines are perpendicular hence the figure formed is a rectangle
let the equation of BC be x-y+k=0 sub C we get k=1
let the equation of CD be x+y+c=0 sub C we get c=-9
solving BC and AB we get B(1,2)
solving CD and AD we get D(3,6)