A graphing calculator shows the value of n is
59.
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Squaring the equation gives
n+5 -2√((n+5)(n-10)) + n-10 = 1
2n - 6 = 2√(n² -5n -50) . . . . . . subtract 1, add the radical term
n² -6n +9 = n² -5n -50 . . . . . . . divide by 2 and square both sides
59 = n . . . . . . . . . . . . . . . . . . . . .add 50 -n² +6n