Find r, if 6r7\(_8\) = 511\(_9\)

Explanation

6r7\(_8\) = 511\(_9\)

6 x 8\(^2\) + r x 8\(^1\) + 7 x 8\(^0\) = 5 x 9\(^2\) + 1 x 9\(^1\) + 1 x 9\(^0\)

6 x 64 + 8r + 7 x 1 = 5 x 81 + 9 + 1 x 1

384 + 8r + 7 = 405 + 9 + 1

8r = 415 - 391

 8r = 24

r = \(\frac{24}{8}\)

= 3

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