Finding intersection of two column data

Here's how I think I would do it:

1) The point of intersection is the point where y1=y2 or y1-y2=0. So the first thing I'd do is add a column calculating y1-y2
2) Since you don't want to use a curve fitting algorithm, the next algorithm I think of is a linear interpolation algorithm. Linear interpolation is a common discussion item here, so you might put that into the site's search engine. In short:
a) Look up the interval in y1-y2 that contains zero (=MATCH() works well for this)
b) Return the X values and Y1-Y2 values that bracket this point (INDEX() function works well for this)
c) Use an appropriate equation (point slope form of a straight line equation or the TREND() function work well) to estimate the X value where Y1-Y2=0
3) Then you will need to use linear interpolation again to locate Y1 or Y2 at the estimated X value.