What is the multiplicative inverse of 2x/5?

Multiplicative inverse is the thing you multiply a term by to get 1.

So 1/2 is the multiplicative inverse of 2 (as an example).

So "flip" the fraction term 2x/5 to get 5/2x ... multiply the two terms together to double check.

2x/5 * 5/2x = 1

So it's 5/2x