Go to youtube and watch till you fall asleep every night;  zero down,  creative deals,   lease options,  subject to..As a realtor you may talk to possible listings that you ask, what is your balance of your mortgage and after subtracting cost to fix up, 10% cost to sell, they have zero or nearly zero equity and thus can't get through a closing and pay the commissions and closing costs.   

Would I just simply multiply all three properties and then subtract with the new refinanced loans ($450k - 337.5k = 112.5k equity)?

Your goals might be different -- define the goal and then see if the property meets that criteria.You might want to consider running numbers in the BiggerPockets calculator, but they have a fantastic rule of thumb to help quickly gauge cash flow and COC return -- take total monthly rent x 50% ($1,125 per month), add your PITI (lets call it $1,175 per month - $650 mortgage, $425 taxes, $100 insurance), add up those two numbers (1125+1175 = $2300 per month), and subtract from your monthly rent of $2,250...based on that model, you'd be looking at a $50 cash flow loss per month.

Unless rents for a 2 br 3 ba townhouse are $3500 plus in that area (which is unlikely)..I'd say absolutely not.On townhouses I automatically subtract the HOA fee from monthly rent to figure my 1% rule.

If I subtract the number of apartments from the housing units, I get 697,395.

I essentially put 50k into the deal in 2014 (20% down payment) and would profit after paying my mortgage off of 200k (150k once you subtract out my initial investment).

Although you subtract a hefty amount of monthly rent (25%) under the Capex umbrella you will want to know your monthly, bimonthly and/or quarterly recurring expenses so breaking out recurring repairs and utilities will help you monitor your investment's performance.      

Once you figure out all of these expenses, subtract from the monthly income to see if it cash flows. 

Rent * 75% - PITI.If that yields a positive number, PITI has already been counted (when we subtracted) and you add that (the resulting positive number) as mortgage qualifying income.

They recalc by using only 75% of the rental income then subtract your reported expenses (i believe they put depreciation deductions back in since they realize they are non-cash deductions).