PLEASE HELP! Electric Fields for 3 charges

Referring to the diagram, Q1 = 7.00°C, Q2 = -7.00uC, Q3 = 7.00uC, y = 4.00cm and x = 5.00cm. What is the magnitude
of the electric field at Q2, due to Q1 and Q3?

Select light for the type of wave, adjust the wavelength so that the light is red, and increase the amplitude of the light to the max. then, select the start button at the source location to begin producing the waves. light is a form of electromagnetic wave, containing oscillating electric and magnetic fields. the wave amplitude detector mentioned above shows how the electric field oscillates in time at the location of the probe. the amplitude of the wave at the location of the probe is equal to the maximum electric field measured. how does the amplitude of the wave depend on the distance from the source?