jika a log5=x dana log7=y maka a log√1.4

[tex]^a log5=x \\ ^a log7=y \\ \\ ^a log \sqrt{1.4} = ^a log { (\frac{14}{10}) }^{ \frac{1}{2} } \\ = \frac{1}{2} (^a log2 + ^a log7 - ^a log2 - ^a log5) \\ = \frac{1}{2} (y - x)[/tex]