Answer
1.4
Work Step by Step
We are given $log_{b}3=.5$ and $log_{b}5=.7$.
We know that $log_{b}x^{r}=rlog_{b}x$ (where $x$ and $b$ are positive real numbers, $b\ne1$, and $r$ is a real number).
Therefore, $log_{b}25=log_{b}5^{2}=2log_{b}5=2(.7)=1.4$.