To solve this problem, we will first simplify each expression separately and then perform the division.

For the first expression:
(1/2x - 2 1/4) ÷ 1.5
Convert 2 1/4 to an improper fraction:
(1/2x - 9/4) ÷ 1.5
Since 1.5 is equivalent to 3/2:
(1/2x - 9/4) ÷ 3/2
To divide by a fraction, we multiply by its reciprocal:
(1/2x - 9/4) * 2/3
Now we distribute the 2/3:
(2/6x - 18/12)
Simplify:
(1/3x - 3/2)

For the second expression:
3.4 ÷ 1.2
Simply divide 3.4 by 1.2:
3.4 ÷ 1.2 = 2.83333...

Putting it all together:
(1/3x - 3/2) = 2.83333...

Therefore, the solution is:
1/3x - 3/2 = 2.83333...