(8/7+14/3+39/2-1/4)x(-7/39)=-8/39-98/117-7/2+7/156=-24/117-98/117-7/2+7/156=-1-5/117-7/2+7/156=-4-5/117-1/2+7/156=-4-20/468-234/468+21/468=-4-233/468=-4又233/468