Your question is a little unclear. Is the $1500 the current balance in the unearned revenue account or is it the current period's unearned revenue? Also, by putting the 500 in parenthesis it appears as if the recognition is a negative amount, e.g. a loss or a write-off.

If current period unearned revenue is $1500 and they also recognized $500 of previous unearned revenue as current revenue, e.g. the (500) indicates they "withdrew" 500 from the unearned revenue account and recognized it as revenue in the current period, then the net change to the unearned revenue account is:

+1500 - 500 = $1000, and the increase in this liability account is a source of cash, and the $500 will show in net income.

If all the other cash outflows on the CF statement are shown as negatives, like the "(500)" is, then the above is a reasonable assumption.

With no other revenues, your CF statement reconciliation would look like this (indirect method)...

Net income: $500

Increase in liabilities: 1,000

Net cash flow: $1500
Sorry I couldn't be more definitive, but the language is a little unclear.

If in the year 2000 the company's statement of cash flor states that unearned revenue is 1500 and the recognition of unearned revenue from prior periods is (500)...what is the change in deferred rev.

I'm not sure if it's 1500 or 2500