How To Evaluate Logarithms?

Use the definition: if ( log_b(x) = y ), then ( b^y = x )

Rewrite the logarithm as an exponential equation

Solve for the exponent

Check that the base is positive and not equal to 1

Check that the argument is positive

Use log properties when needed:

( log_b(MN) = log_b(M) + log_b(N) )

( log_b!left(frac{M}{N}right) = log_b(M) – log_b(N) )

( log_b(M^k) = klog_b(M) )

( log_b(b) = 1 )

( log_b(1) = 0 )

Use common special values:

( log_b(b^k) = k )

( log_{10}(10^k) = k )

( ln(e^k) = k )

If the base is not convenient, use change of base:

( log_b(x) = frac{log(x)}{log(b)} )

( log_b(x) = frac{ln(x)}{ln(b)} )

Simplify the expression before evaluating

Substitute known values and compute the result

Verify the final answer satisfies the original logarithm

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