Trendline Equation When Solved for X (as seen on graph) Does NOT Match

Hello All,

I am working on staffing projections so I can create a budget for 2019 based off of projected growth. Seems simple enough, but I wanted to use a trendline equation for active staff (green) instead of rough percentages, which looks good on the graph but yields bizarre results when I plug in the excel number for the dates I'm looking for (12/01/2019=43388).

I read that not having enough decimal places to see the full equation could create problems so I added in 30 decimal places. I also checked my math on Wolfram Alpha and got the same result. In the attached graph/ image it looks like I should expect a number around 180. When I solve the equation I get 155.54 in both excel and Wolfram Alpha. Any ideas on whats causing this and how I can get the correct equation for the (green) visual trendline?

Thank you!

Where did you get that 1 Dec 2019 is serial number 43388? Using the 1900 date system, I get that 43388 is the serial number for 15 Oct 2018 and the serial number for 1 Dec 2019 is 43800. 43800 in that equation gives me 188. I suggest that you double check the date serial number you are using.