9514 1404 393
Answer:
x = 9
Step-by-step explanation:
The applicable rule of logarithms is ...
log(a) -log(b) = log(a/b)
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Use the rules of logarithms to simplify the left side to a single log, then take the antilogs and solve the resulting equation.
log(x+1) -log(x-8) = log(10)
log((x+1)/(x-8)) = log(10)
(x +1)/(x -8) = 10 . . . . . . . take antilogs
x +1 = 10(x -8) . . . . multiply by x-8
81 = 9x . . . . . . . add 81-x, simplify
9 = x . . . . . . . . . divide by 9
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When the equation is rewritten to the form f(x) = 0, the x-intercept is the solution.
