The first three negative integers are: -1, -2 and -3.
Associative property in multiplication:
a x (b x c) = (a x b) x c
Verifying with a= -1, b= -2 and c= -3:
=> a x (b x c) = -1 x (-2 x -3) = -1 x (6) = -6
And, (a x b) x c = (-1 x -2) x -3 = (2) x -3 = -6
This means that the property holds true in multiplication of the first three negative integers.