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anonymous
 5 years ago
If 4^x +4^(x) = 7, hence 8^x +8^(x) = .......
anonymous
 5 years ago
If 4^x +4^(x) = 7, hence 8^x +8^(x) = .......

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anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0log x to the base 4 + log  x to the base 4 = 7 Im unsure if thats right

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0the choices are : a) 15 b) 18 c) 21 d) 24 e) 30

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Its 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

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0that's right the answer is 18. but how do you get x around 1.4? i dont understand.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0first 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
 5 years ago
Best ResponseYou've already chosen the best response.0haha you dont want it? should i undo that?

watchmath
 5 years ago
Best ResponseYou've already chosen the best response.1Begini 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 \((a^3+a^{3})^2=(a^2+a^{2})^3+23(a^2+a^{2})\)..............(*) Sekarang ambil \(a=2^{x}\) Maka kita peroleh \(a^2+a^{2}=7\) dan kita inging mencari \(a^3+a^{3}\) Dari (*) kita peroleh \(a^3+a^{3}=7^3+23(7)=324\) Dengan demikian \(a^3+a^{3}=\sqrt{324}=18.\)
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