Finding the rate equation and rate constant

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1. The problem statement, all variables and given/known data

The dissociation of a compound was studied by performing measurements of
a quantity X that is proportional to the concentration of the compound. The values of X measured at various times are as follows:

X--->1.82, 2.01, 2.31, 2.67, 3.80, 5.25
t/sec----> 521, 617, 749, 873, 1185, 1449

Use this information to form a rate equation and rate constant.

2. Relevant equations

k= (ln {A(t)/A(0)})/t

3. The attempt at a solution

Im having a bunch of problems with this question and need a bit of a jump start.

1) the value of X: I am not given units or anything. It could basically be anything right?

2) the question states that X is proportional to the concentration of the compound. It also implies that the compound is dissociating. If you noticed, as time goes on, X is increasing. If they are proportional to each other how can the compound dissociate when X is increasing. My only thought is that they are "inversely" proportional and the question just says proportional.

3) Assuming that X has units of concentration, I went ahead and calculated the rate constant and got virtually all the same values (implying first order reaction) but the values were all negative. This is because X is increasing. Can I safely assume that these values of X are to do with concentration and assume that they are products and therefore use numbers that decrease proportionally to the given values and come up with a positive rate equation?

Thankyou for your time
1. The problem statement, all variables and given/known data



2. Relevant equations



3. The attempt at a solution