(x/5)^log_b(5) - (x/6)^log_b(6) = 0

      • siriusmart@lemmy.worldM
        2·
        6 months ago

        i showed the question to my friend who isnt particularly bright in maths, he said 30 by just looking at it, i freaked out a bit but it might just have been a lucky guess

    • zkfcfbzr@lemmy.worldOPEnglish
      0·
      6 months ago

      Yes, though I prefer spoilered answers with work (especially since something like Wolfram|Alpha can just spit out the answer here)

      I’m curious about your retracted edit, since I saw your original message had just the correct answer - why 30k?

      • Lojcs@lemm.ee
        0·
        6 months ago

        I thought 0 also works so maybe it’s multiples of 30 but then tried 60 and it didn’t work

        • zkfcfbzr@lemmy.worldOPEnglish
          0·
          6 months ago
          spoilers

          0 does work as a trivial solution, since 0^a = 0^b always holds, but yea, 30’s the only other one - the key comes down to the fact that a^log(b) = b^log(a) in general, and 30 is what achieves that here