X ÷ 9 = 4 I dont know what this answer is?

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?

Questions 7-8. use the following table to answer. year 2006 2007 2008 2009 2010 2011 2012 2013 cpi 201.6 207.342 215.303 214.537 218.056 224.939 229.594 232.957 7. suppose you bought a house in 2006 for $120,000. use the table above to calculate the 2013 value adjusted for inflation. (round to the nearest whole number) 8. suppose you bought a house in 2013 for $90,000. use the table above to calculate the 2006 value adjusted for inflation. (round to the nearest whole number)

Present age of man is 45 years, 5 years back his age was 4 times age of his son what is present age of his son?