The property is multiplicative inverse property
The multiplicative inverse property states that every non-zero number has an inverse such that the product of a number and its inverse equals 1.
For example, the multiplicative inverse of 3 is 1/3, as 3 * (1/3) = 1. Another example is x/y,the multiplicative inverse of x/y is y/x.
3x/2 , the multiplicative inverse of 3x/2 is a number that will give 1 when they are multiplied.
Therefore, the multiplicative inverse of 3x/2 is 2/3x
3x/2 × 2/3x = 1