\( \frac{4x-4y+ax-ay}{x^2-y^2} = \frac{4(x-y)+a(x-y)}{(x-y)(x+y)} = \frac{(x-y)(4+a)}{(x-y)(x+y)} = \frac{4+a}{x+y} \)
Подставим значения \( a = 2, x = 7.3, y = -7.8 \):
\( \frac{4+2}{7.3+(-7.8)} = \frac{6}{7.3-7.8} = \frac{6}{-0.5} = -12 \)
Ответ: -12