Question

Solve the equation for x by first making an appropriate substitution, such as u = e^x.
5e^2x-21e^x+4=0

x = (smaller value)
x = (larger value)

Answer 1

5u^2 - 21u + 4 = 0
(5u -1)(u - 4) = 0
u = 0.2 or u = 4

Answer 2

e^x. = 4 then x = 1.386
e^x = 0.2 then x = -1.609

Answer 3

ty

Answer 4

jimmyrep, you're awesome! thanks for all the help!

Answer 5

no probs - tell my grand daughter that - shes on the picture with her cat

Answer 6

haha. i wondering why ur name is jimmy but u have a pic of a female.

Answer 7

yep

Answer 8

wait how did u get the final answers? i cant seem to get them when i type them in my calc