Answer the amplitude part of the questions in 7, 8, & 9

I actually believe for the first question, it would be complete destructive interference as the amplitude and the approximate wavelength for each are the same and will completely or entirely cancel out, rather than simply decreasing or lowering the amplitude as in the bottom question.

The amplitude for the first will be 0, as the 2 waves will cancel each other out. The amplitude of the second, will be 3x, I believe, assuming the amplitude of the first is 2x and the second is 1x, in a constructive interference, I believe the amplitudes would add up.

Likewise for the bottom, I believe you would be subtracting the supposed amplitude of the first which is 2x from 1x which would be 1x.

Iknow the first part it is the average star i am not 100% sure