Answer:

Step-by-step explanation:
Using the magnetic field equation:

where:
 = permeability of free space =
 = permeability of free space = 

I = current in the wire
r = distance from the wire to the point 
Magnetic field due to the wire on the x- axis can be calculated as:



Magnetic field due to the positive z-direction wire:



Now; adding these two vector components together to get the magnitude of the resultant vector; we have:
= 

= 
