Answer:
hello your question has some missing information attached below is the missing information
answer : q3 = 0.300 nC
Step-by-step explanation:
Given that Eay is in the Y axis ( upward ) , E3 will be downward and this will make the sign on the the charge ( q3 ) to be positive
E3 = Eay. ( for an electric field to be neutral/zero the electric field in the opposite direction will have same magnitude )
To calculate the value of q3 we will apply the relation below
K*q3/( 15 - 12 )^2 = 0.300
= (9 * 10^9) * (q3 / 9 ) = 0.300
∴ q3 = 0.300 / 10^9
= 0.300 nC
Note : The value of Eay is been calculated outside this solution as it is not part of the question asked