The question is incomplete, we can notice that from from () in between the question.
The correct question is:
A particle of charge on the y-axis a distance a from the origin and a second particle of charge is on the x-axis a distance d from the origin. The magnitude of the x-component of the force on the second particle is:
Answer:
d=

Step-by-step explanation:
given
distance from origin on y axis = a
distance from origin on x axis = d
attached is an equation that further explains how we got the answer