anonymous
  • anonymous
If 4^x +4^(-x) = 7, hence 8^x +8^(-x) = .......
Mathematics
  • Stacey Warren - Expert brainly.com
Hey! We 've verified this expert answer for you, click below to unlock the details :)
SOLVED
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
katieb
  • katieb
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
anonymous
  • anonymous
log x to the base 4 + log - x to the base 4 = 7 Im unsure if thats right
anonymous
  • anonymous
the choices are : a) 15 b) 18 c) 21 d) 24 e) 30
anonymous
  • anonymous
Its 18 ( option b) Through trial and error you find x to be something around 1.4 Substitute that value in the second formula you get 18.4 So the answer is 18

Looking for something else?

Not the answer you are looking for? Search for more explanations.

More answers

anonymous
  • anonymous
that's right the answer is 18. but how do you get x around 1.4? i dont understand.
anonymous
  • anonymous
first try x = 2 in the first formula its too high so then i tried x as 1.5 It was closer !.3 was too low 1.4 was pretty close I finally got it as somewhere around 1.39
anonymous
  • anonymous
thankyou :)
anonymous
  • anonymous
medal??
anonymous
  • anonymous
just kidding
anonymous
  • anonymous
haha you dont want it? should i undo that?
watchmath
  • watchmath
Begini Dinda, \((a^3+\frac{1}{a^3})^2=a^6+2+\frac{1}{a^6}\) \((a^2+\frac{1}{a^2})^3=a^6+3a^2+\frac{3}{a^2}+\frac{1}{a^6}\) Akibatnya \((a^3+a^{-3})^2=(a^2+a^{-2})^3+2-3(a^2+a^{-2})\)..............(*) Sekarang ambil \(a=2^{-x}\) Maka kita peroleh \(a^2+a^{-2}=7\) dan kita inging mencari \(a^3+a^{-3}\) Dari (*) kita peroleh \(a^3+a^{-3}=7^3+2-3(7)=324\) Dengan demikian \(a^3+a^{-3}=\sqrt{324}=18.\)

Looking for something else?

Not the answer you are looking for? Search for more explanations.