Respuesta :
[tex]F=\frac{\mu_0\cdot I_1\cdot I_2}{2\pi\cdot d}\cdot l[/tex]
Based on the formula we have two currents with the same direction, we know this due to the attractive force.
Also, we don't have information about the length l of the wires, but thanks to the force which is expressed in terms of Newtons per length we can avoid it.
[tex]\begin{gathered} \frac{F}{L}=3\cdot10^{-3}N/m=\frac{425A\cdot5A}{2\pi\cdot d}\cdot4\pi\cdot10^{-7}N/A^2 \\ d=0.1417m \end{gathered}[/tex]