Let's say I have two columns of data like this:

x y
147 46.8
148 48.2
149 49.6
150 50.4
151 51.2
152 52.6

I want to find what x value corresponds to a value of y = 50. For example in this data, at y = 50, x =149.5. So essentially I have to search for an interpolated value that isn't actually in the data.

I've tried getting the equation of a line using SLOPE() and INTERCEPT() and then solving for x, but this has given me inaccurate results.