√81 = 8+1. What About 4-Digit Numbers?

My previous video explaining √81 = 8+1:    • Is 81 the ONLY Two-Digit Number with ...  

My video on √81 = 8+1 went viral, and viewers pointed out that finding two-digit numbers are too easy that it can be done by bashing (testing every perfect squares), urging me to expand the problem with more digits. So here I present you how to find all 4-digit numbers xyzw satisfying the relation √(xyzw) = xy + zw. Since the RHS consists of only 2 numbers, we can use the same quadratic equation method used in my previous video.

#NumberTheory #DiophantineEquations #IntegerRoot

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