Question 468194
2e^2x+5e^x-12=0
let e^x=u

2u^2-5u-12=0

2u^2-8u+3u-12=0
2u(u-4)+3(u-4)=0

(u-4)(2u+3)=0
e^x=4 

ln(e^x)= ln(4)
x= ln(4)

e^x= -3/2
x=ln(-3/2) not defined