It's the first one, an algebraic expression contains variables
Answer:

Step-by-step explanation:
We want to find the rational number which is equal to
.
Let
....eqn(1)
Multiply both sides by 10
.....eqn (2)
Subtract eqn (1) from eqn (2)


Divide both sides by 9.

512 there good luck hope u do good if u have any questions let me know
4/31. There's no more simplified version than that.