function simple ....but the answer not logic for me

1. Given set A = {9, 36, 49, 64} and set B = {-8, -6, 3, 4, 6, 7, 8}. The relation from set A

to set B is "the square root of ", state

(a) the range of the relation,

(b) the object of 8,

(c) the image of 49.

[ 3 marks ]

ans given:

a) {3,6,7,8} ---- my ans { 8,7,6,3,-6,-8}

b) 56 ---- my ans 64

c) 7 ---- my ans 7 (logic)

hope i can get help

below is my arrow diagrame:

http://img155.imageshack.us/my.php?i...mathvi4.th.png

and the calculation of mapping as below

calculation "the square root of "

(a) the square root of 9 is +3 or -3 (-3 ignore)

(b) the square root of 36 is +6 or -6

(c) the square root of 49 is 7 or -7 (-7 ignore)

(c) the square root of 64 is +8 or -8