[3x/(x+2)-x/(x-2)]/[2x/(x^2-4)]
={3x(x-2)/[(x+2)(x-2)]-x(x+2)/[(x+2)(x-2)}/[2x/(x^2-4)]
={[2x(x-2)]/[(x+2)(x-2)]}/{2x/[(x+2)(x-2)}
=x-2