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D( x )
x = 0
x = 0
x = 0
x in (-oo:0) U (0:+oo)
1-(52.12/x) = 0.75 // - 0.75
1-(52.12/x)-0.75 = 0
1-52.12*x^-1-0.75 = 0
-52.12*x^-1 = -0.25 // : -52.12
x^-1 = 0.00479662
-1 < 0
1/(x^1) = 0.00479662 // * x^1
1 = 0.00479662*x^1 // : 0.00479662
208.4801381 = x^1
x = 208.4801381
x = 208.4801381
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