well you have to use one of the logarithm laws
b * ln (x) = ln (x^b)
So
2 ln (2x + 5) = 8
ln [(2x+5)^2] = 8
So now if we do e^x on both sides and we say that x is going to be what either side equals like this
e^(ln [(2x+5)^2]) = e^8
We we know that
e^[ln (x)] = x so
[(2x+5)^2] = e^8
take square root of both sides
2x + 5 = e^4. and -(2x+5) = e^4
2x = e^4 - 5. and -2x = e^4 + 5
x = (e^4 - 5)/2 and x =(e^4 + 5) / -2
now just use a calculator to solve
