Yes rational expression and its simplified forms are equivalent.
Rational expression are those that contain fractions.
Example:
25/50 is a rational expression but it is not yet in its simplest form.
25/50 ⇒ 5/10 ⇒ 1/2
1/2 is the simplest form of 25/50.
They are equivalent:
1/2 = 25/50
1*50 = 2*25
50 = 50
or
1/2 = 0.50
25/50 = 0.50