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# Logarithm question watch

1. Hi i need help i've been stuck for hours on a set of questions with the same format. I know the answer via the answer page but i really want to know how i would go about getting to that answer.
find the value of x which satisfies each equation
2^2x+1 - 13(2^x)+20=0
and solve for x
log(base2)X + log(base3)X = 1

Why not try posting in a specific subject forum- you might have more luck there.

Here's a link to our subject forum which should help get you more responses.

3. (Original post by uchihaitachi0023)
Hi i need help i've been stuck for hours on a set of questions with the same format. I know the answer via the answer page but i really want to know how i would go about getting to that answer.
find the value of x which satisfies each equation
2^2x+1 - 13(2^x)+20=0
and solve for x
log(base2)X + log(base3)X = 1
For the first one, try the substitution so you can transform it into a more explicit quadratic.

For the second one, you will need to change the base of one of the logarithms and then you can use the multiplication rule to solve them.

Have a go and let me know if you need any more help
4. (Original post by uchihaitachi0023)
Hi i need help i've been stuck for hours on a set of questions with the same format. I know the answer via the answer page but i really want to know how i would go about getting to that answer.
find the value of x which satisfies each equation
2^2x+1 - 13(2^x)+20=0
and solve for x
log(base2)X + log(base3)X = 1
2^2x+1 = 2^2x * 2^1

and use change of base rule for 2nd question
5. for the second one I do
Log(base3)x/logbase(2) + log(base3)x=1
Then I get log(base3)x^2/2 = 1
Is this right so far?

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Updated: March 26, 2016
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