A car dealer leases a supercomputer with machine learning software for $5000. The improved productivity and reduced labor costs result in net savings of $1000 per year, increasing at $50 per year for each year it is in use for its estimated life of 10 years. How long does it take to recover the initial investment at 10% per year interest rate. (Hint: You may need a numerical method like bisection search, or Excel goal seek function