Solving systems of equations in three variables

x+y-z=-1
x+y+z=3
3x-2y-z=-4

Circle d circumscribes abc and abe. which statements about the triangles are true? statement i: the perpendicular bisectors of abc intersect at the same point as those of abe. statement ii: the distance from c to d is the same as the distance from d to e. statement iii: bisects cde. statement iv: the angle bisectors of abc intersect at the same point as those of abe. a. i only b. i and ii c. ii and iv d. i and iii e. iii and iv