SOLUTION: solve for x.... logx64=-6

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Question 354710: solve for x.... logx64=-6
Answer by jsmallt9(3758) About Me  (Show Source):
You can put this solution on YOUR website!
With an equation of the form
log(expression) = other-expression
and the variable in the argument or base of the logarithm, then you will usually rewrite the equation in exponential form. In general, log%28a%2C+%28p%29%29+=+q is equivalent to a%5Eq+=+p. Using this on your equation we get:
x%5E%28-6%29+=+64
Rewriting this with a positive exponent we get:
1%2Fx%5E6+=+64
We can eliminate the fraction by multiplying both sides by x%5E6:
1+=+64x%5E6
Next we can divide both sides by 64:
1%2F64+=+x%5E6
To find x we will find the 6th root of each side:
root%286%2C+1%2F64%29+=+root%286%2C+x%5E6%29
(Since x is the base of a logarithm in this problem, we can ignore the negative 6th roots of 64. Bases of logarithms must be positive!) Since 2%5E6+=+64 we get 1/2 on the left side:
1%2F2+=+x