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I think you mean (at least on the Mac) shift command E. (it also is the menu item Cell/ShowExpression)
I have some doubts that there are more than one solution, at least in the unit square. The following plots show ony one likely candidate: Plot3D[{Sqrt@Norm[{exp3 - tP/(1 - tP), exp6 - tC/(1 - tC)}], 0}, {tC, 0, 1}, {tP, 0, 1},...