## Algebra: A Combined Approach (4th Edition)

{$8$}
Step 1: $\log_{x} 64=2$ Step 2: $x^{2}=64$ Step 3: $\sqrt {x^{2}}=\pm\sqrt {64}$ Step 4: $x=+8$, as -8 is discarded since the base of a logarithm cannot be negative. Therefore, the solution set is {$8$}.