$$\left. \begin{array} { l } { b = 1 \cdot 25 m } \\ { 65 c m = 0.5 m } \end{array} \right.$$
$b=25m\text{, }m\in \mathrm{R}\text{, }c=\frac{1}{130}\approx 0.007692308$
$b=0\text{, }m=0\text{, }c\in \mathrm{R}$
