SOLUTION: solve for u log3 (u + 18) + log3 (u) = 5

Question 447944: solve for u
log3 (u + 18) + log3 (u) = 5
Found 2 solutions by stanbon, Alan3354:
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
solve for u
log3 (u + 18) + log3 (u) = 5
-------------------
log3[u(u+18)] = 5
----
u^2+18u = 3^5
---
u^2+18u-243 = 0
---
(u-9)(u+27) = 0
---
Positive solution:
u = 9
==========================
Cheers,
Stan H.
==========================
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!

(u+27)(u-9) = 0
-27 gives log of neg #s, reject
u = 9

RELATED QUESTIONS
how do u solve 2 log3 (x+4)- log3... (answered by stanbon,kdepasquo137)
solve for u... (answered by vleith)
solve for u 3/17=u/5 (answered by onlinetutor365.com)
solve for u 45 =... (answered by Alan3354)
(u+5)/(u+4)=[(u+4)/(u+6)]+1 How do I solve for... (answered by Tatiana_Stebko)
solve for u:... (answered by Fombitz)
solve for X.... (answered by lwsshak3)
6u+5(u+3)=4 solve for... (answered by nyc_function)
Solve for u 1 divided by u - 5 =... (answered by oberobic)