Data Sufficiency

hello everyone!

I can't fully understand the meaning of the question no. 104 DS in 13th OG. what exactly are those parentheses with x and how i know that it is equivalent to 0<= x < 1?

thanks a lot

Michal

Please post the problem itself, not just the question number.
Here is DS104 in the OG13:

If [x] denotes the greatest integer less than or equal to x , is [x] =0?
(1) 5x + 1 = 3 + 2x
(2) 0 < x < 1

{x} = 0 implies that the GREATEST INTEGER LESS THAN OR EQUAL TO X is 0.

If 0≤x≤1, then the greatest integer less than or equal to x is 0.
Consider the following cases:
x=0 -------> The greatest integer less than or equal to 0 is 0.
x=0.0001 --> The greatest integer less than or equal to 0.0001 is 0.
x=0.9999 --> The greatest integer less than or equal to 0.9999 is 0.

If x<0 or x≥1, then the greatest integer less than or equal to x will NOT be 0.

Question stem, rephrased:
Is 0≤x≤1?

Statement 1: 5x + 1 = 3 + 2x
Since we can solve for x, we can determine whether 0≤x<1.
SUFFICIENT.

Statement 2: 0 < x < 1
SUFFICIENT.

The correct answer is D.

sorry, the next time I ll write also the question itself.
and thank you very much for your answer.