Find the solutions of the exponential equation

e^(2x)-5e^(x)+6=0

let z = e^x

(e^x)^2 = e^(2x)
so
z^2 - 5 z + 6 = 0
(z-2)(z-3) = 0
z = 2 or z = 3
if e^x = 2
x = ln 2
if e^x = 3
x = ln 3