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Sunday, May 15, 2022

2022/039) Find x integer such that \frac{8^x - 2^x }{6^x - 3^x} = 2

 We have numerator = 8^x - 2^x = (2^3)^x - 2^x = (2^(3x) - 2^x = 2^x(2^{2x} - 1)= 2^x(2^x + 1)(2^x-1)

Denominator = 6^x - 2^x = 3^x(2^x-1)

So \frac{8^x - 2^x }{6^x - 3^x} = \frac{2^x(2^x+1)}{3^x} = 2

Or 2^x(2^x+1) = 2 * 3^x

x cannot be zero as in the original question x = 0 is not possible

So we must ahve 2^x = 2 and 2^x+ 1 = 3^x by equating even on both sides and odd on both sides

1st equuation gives x = 1 and it satisfies 2nd equation as well.

so Solution x = 1 


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