1.Solve, 3^2x = 5^(1-x) 2. Solve 4^2x - 8(2^2x) - 9 =0
Last edited by nav92; Oct 31st 2010 at 12:27 AM. Reason: Sorry i mistyped on question 1..it's 3^2x not 5^2x..
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Take logarithms to the base 5 on both sides. You have which is a simple linear equation in one variable.
For the second one, use the substitution:
For the second one, The answer must be in 3 significant numbers which I can't seem to get......Instead I get, After substitution, y^2 - 8y - 9 = 0 y= 9 ; y= -1
Right, now, replace y by 2^2x again
Oh man , how could i missed the substitution part on question 2...okay i get it What about question 1 where the base number is different?
Hm... let's do it. Take logs on both sides. Bring xlog5 to the left; Factor x; Can you continue now?
Originally Posted by nav92 Oh man , how could i missed the substitution part on question 2...okay i get it What about question 1 where the base number is different? Re-write the equation: Multiply through by and you'll get: I'll leave the rest for you.
Yes this had really helped a lot.....Question solved.
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