Question

Given that
cos
⁡
�
=
6
4
cosx=
4
6
​

​
and
cos
⁡
�
=
2
4
cosy=
4
2
​

​
, and that angles
�
x and
�
y are both in Quadrant I, find the exact value of
sin
⁡
(
�
−
�
)
sin(x−y), in simplest radical form.