Since the bases are not matching, we can use logarithms to
solve exponential equations.
We'll take logarthims both
sides:
log5 [5^(11x-1)] = log5
(7^x)
We'll apply the power rule for
logarithms:
(11x-1) log5 5 = x log5
7
We'll recall that log5 5 =
1
We'll re-write the
equation:
11x-1 = x log5
7
We'll subtract x log5 7 both
sides:
11x - x log5 7 =
1
We'll factorize by x:
x(11 -
log5 7) = 1
We'll re-write log5 7 =
lg7/lg5
x(11 - lg7/lg5) =
1
We'll divide by 11 - lg7/lg5 =
9.7909
x = 1/9.7909
Rounded to
four decimal places:
x =
0.1021
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