7. Найдем значение выражения
$$\frac{6-3a}{8a+4b} - \frac{4a^2+4ab+b^2}{a-2}$$
при $$a = 6$$ и $$b = -4$$.
$$\frac{6-3(6)}{8(6)+4(-4)} - \frac{4(6)^2+4(6)(-4)+(-4)^2}{6-2}$$
$$\frac{6-18}{48-16} - \frac{4(36)-96+16}{4}$$
$$\frac{-12}{32} - \frac{144-96+16}{4}$$
$$\frac{-12}{32} - \frac{64}{4}$$
$$\frac{-3}{8} - 16 = \frac{-3}{8} - \frac{16 \cdot 8}{8} = \frac{-3 - 128}{8} = \frac{-131}{8} = -16 \frac{3}{8} = -16.375$$
Ответ: -16.375