Solve the logarithmic equation Be sure to reject any value o
Solution
Given
log8 x +log8 (7x-1) = 1
Using
logb(m) + logb(n) = logb(mn) // if the base of log terms are same then we can multiply the terms inside log
log8 (x(7x-1)) = 1
distributing \"x\" over the bracket
log8 (7x2 - x) = 1
7x2 - x = 81 // logb a = c => a = bc
7x2 - x = 8
7x2 - x - 8 = 0
7x2 -8x +7x -8 = 0
x(7x - 8) +1(7x-8) = 0
(7x - 8)(x + 1) = 0
x = 8/7 or x = -1
for x = -1 we cannot consider this solution as log is not defined for negative numbers
therefore the solution is x = 8/7
