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Name the base (Posted on 2023-02-07) Difficulty: 3 of 5
Given:
x2-17x+73=0 .
In what base is there a solution of two Integers of the above equation ?

No Solution Yet Submitted by Ady TZIDON    
Rating: 4.0000 (2 votes)

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the computer method | Comment 2 of 4 |
clearvars
for base=8:25
   a=1;
   b=-(base+7);
   c=7*base+3;
   r=roots([a,b,c]); % roots solves polynomial with given coefficients
   disp(base)
   disp(r)
   disp(' ')
end

tries bases 8 through 25 and finds

   base       roots
          -------------------------------------------
     8
                        7.5 +       1.6583123951777i
                        7.5 -       1.6583123951777i
 
     9
                          8 +       1.4142135623731i
                          8 -       1.4142135623731i
 
    10
                        8.5 +     0.866025403784449i
                        8.5 -     0.866025403784449i
 
    11
                        10
                         8
 
    12
           11.302775637732
          7.69722436226801
 
    13
          12.4494897427832
          7.55051025721682
 
    14
          13.5413812651491
          7.45861873485089
 
    15
           14.605551275464
          7.39444872453601
 
    16
           15.653311931459
          7.34668806854096
 
    17
          16.6904157598234
          7.30958424017657
 
    18
          17.7201532544553
          7.27984674554472
 
    19
           18.744562646538
          7.25543735346197
 
    20
          19.7649820430708
          7.23501795692917
 
    21
          20.7823299831253
          7.21767001687473
 
    22
          21.7972597596632
          7.20274024033679
 
    23
          22.8102496759067
          7.18975032409335
 
    24
          23.8216584885466
          7.17834151145338
 
    25
          24.8317608663278
          7.16823913367215
          
          
Base 11 results in integral roots 10 and 8.        

  Posted by Charlie on 2023-02-07 08:03:48
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