Question 173572
Solve 
y= log2(5x-4)
y= 3+log2(x-1)
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Substitute to get:
log2 (5x-4) = 3 + log2 (x-1)

log2 (5x-4) - log2 (x-1) = 3

log2 [(5x-4)/(x-1)] = 3


[(5x-4)/(x-1)]  = 2^3

5x-4 = 8(x-1)

5x-4 = 8x - 8

3x = 4

x = 4/3
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Cheers,
Stan H.