DAX for detecting the intersecting point between two lines

[hariskhan12511]

I have three measures:
1. Spend
2. Transactions
3. ROI

I'm plotting these measures in a line chart:
1. Spend on x-axis (converted this to a column to plot it)
2. Transactions on y-axis
3. ROI on secondary y-axis

I'm trying to work out a DAX that returns true on the intersection point when plotted on y-axis

[AlexisOlson]

It seems to me like the intersection is not uniquely determined but depends on the relative scaling of your two y-axes. Is there a natural interpretation of what the intersection means from a business perspective?