Mark M. answered 03/25/21
Retired math prof. Very extensive Precalculus tutoring experience.
8(5x) + 2 = 26
8(5x) = 24
5x = 3
x = log53, or equivalently, log3 / log5 or ln3 / ln5
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logx+15 = 2
(x+1)2 = 5
x+1 = ±√5
x+1 can't be -√5 since the base of a logarithm can't be negative
So, x = -1 + √5