I'm quite stuck on this question. I'd be really appreciative if someone explains it to me

John starts a fund in 1986 with $30,000. In 2004, exactly 18years after the fund was opened, he withdraws 10,000. In 2005, he takes 15,000. In 2006 he takes another 15,000. FInally, in 2007, he withdraws 20,000 and the fund is closed. Determine the internal rate of return using two iterations of Newton-Raphson.

Thanks a lot