Got Homework?
Connect with other students for help. It's a free community.
Here's the question you clicked on:
 0 viewing
trupinoyboi
Group Title
find the exact solution, using common logarithms, and a twodecimalplace approximation of the solution 4^x3(4^x)=8
 11 months ago
 11 months ago
trupinoyboi Group Title
find the exact solution, using common logarithms, and a twodecimalplace approximation of the solution 4^x3(4^x)=8
 11 months ago
 11 months ago

This Question is Open

agent0smith Group TitleBest ResponseYou've already chosen the best response.1
\[\Large 4^x3(4^{x})=8\]first subtract 8 on both sides \[\Large 4^x3(4^{x})8=0\]I would multiply both sides by 4^x \[\Large 4^{2x}38(4^x) = 0\](think about exponent laws and you'll see how to get it. Now it's like a quadratic.
 11 months ago

trupinoyboi Group TitleBest ResponseYou've already chosen the best response.0
im terribly confused as to how i would apply common logarithms to this problem. :(
 11 months ago

Mertsj Group TitleBest ResponseYou've already chosen the best response.2
You could say: Let 4^x=y then you would have : y^28y3=0 Solve for y using the quadratic formula. Set each answer equal to 4^x and take the log of both sides.
 11 months ago

trupinoyboi Group TitleBest ResponseYou've already chosen the best response.0
dw:1386036292570:dw i ended up with this
 11 months ago

trupinoyboi Group TitleBest ResponseYou've already chosen the best response.0
dw:1386036395791:dw would it turn to this?
 11 months ago

agent0smith Group TitleBest ResponseYou've already chosen the best response.1
Can't read that. \[\Large 4^{2x}38(4^x) = 0\]if you understand to here, do as merts said. Let y = 4^x \[\Large y^2 8y  3 = 0\]solve using quadratic formula.
 11 months ago

trupinoyboi Group TitleBest ResponseYou've already chosen the best response.0
I ended up with \[4^x= \frac{ 8+\sqrt{52} }{ 2 }\]
 11 months ago

trupinoyboi Group TitleBest ResponseYou've already chosen the best response.0
The answer i should end up with\[\frac{ \log(4+\sqrt{19)} }{\log4 }\]
 11 months ago

agent0smith Group TitleBest ResponseYou've already chosen the best response.1
Check your math in the quadratic formula, looks like your numbers aren't right.
 11 months ago

Mertsj Group TitleBest ResponseYou've already chosen the best response.2
\[y=\frac{8\pm \sqrt{644(1)(3)}}{2}=\frac{8\pm \sqrt{76}}{2}=\frac{8\pm2\sqrt{19}}{2}=4\pm \sqrt{19}\]
 11 months ago

Mertsj Group TitleBest ResponseYou've already chosen the best response.2
\[4^x=4+\sqrt{19}\] \[x \log_{10}4=\log_{10}(4+\sqrt{19}) \]
 11 months ago

Mertsj Group TitleBest ResponseYou've already chosen the best response.2
Divide both sides by log 4
 11 months ago

trupinoyboi Group TitleBest ResponseYou've already chosen the best response.0
I am so grateful to both of you. Thank you so much! :)
 11 months ago
See more questions >>>
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.