Pearson Algebra 2 Common Core, 2011
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Pearson Algebra 2 Common Core, 2011 View details
Mid-Chapter Quiz
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Exercise 21 Page 461

Set up an equation and apply the definition of a logarithm.

2

Practice makes perfect
To evaluate the given logarithm, we will start by writing a logarithmic equation. log_8 64=x In order to solve this equation, we can rewrite it as an exponential equation by using the definition of a logarithm. log_b x=y ⇔ x= b^y The above means that the logarithm y is the exponent to which b must be raised to get x. For our exercise, y is the exponent to which 8 must be raised to get 64. log_8 64=x ⇔ 64= 8^x Finally, to solve the exponential equation, we will rewrite the terms so that they have a common base.
64 =8^x
8^2=8^x
Now we have two equivalent expressions with the same base. If both sides of the equation are equal, the exponents must also be equal. 8^2=8^x ⇔ x=2