Question

One 4-yuple that satisfies a^2+b^2+c^2+d^2=abcd is (2, 2, 2, 2). What is the largest number x for which (2, 2, 2, x) satisfies a^2+b^2+c^2+d^2=abcd is (2, 2, 2, 2)?

Answer 1

4-tuple*