Решите уравнение: 69-(13-y)^2=-y^2

Question

Решите уравнение: 69-(13-y)^2=-y^2

Answer 1

Удачи................

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Answer 2

69-(169-26y+y^2)=у^2
69-169+26у+у^2=-у^2
69-169+26у=0
-100+26у=0
26у=100
у= 50/13