Đáp án:
`B = x/y + (1/4 + 5/8 - 7/13)/(-2/12 - 10/24 + 14/34)`
`B = x/y + (2/8 + 5/8 - 7/13)/(-4/24 - 10/24 + 7/17)`
`B = x/y + (7/8 - 7/13)/(-7/12 + 7/17)`
`B = x/y + (91/104-56/104)/(-119/204+84/204)`
`B = x/y + (35/104)/(-35/204)`
`B = x/y + 35/104 : (-35/204)`
`B = x/y + 35/104 × (-204/35)`
`B = x/y + (-204/104)`
`B = x/y + (-51/26)`
Thay `x = -5/6, y = -10/11` vào biểu thức B, ta được:
`B = (-5/6)/(-10/11) + (-51/26)`
`B = (-5/6) : (-10/11) + (-51/26)`
`B = (-5/6) × (-11/10) - 51/26)`
`B = 11/12 - 51/26`
`B = 286/312 - 612/312`
`B = -163/156`
