`2`
`a) [(1/8 : 8/27) : -1/3] : 81/128`
`= [27/64 : -1/3] : 81/128`
`= 81/-64 : 81/128`
`= 10368/-5184 = -2/1`
`b) (-7/15) × 5 /8 - 15/-7 - (-32)`
`= (-7/15) × 5 /8 - 15/-7 - (-32)`
`= (-35/120) - 15/-7 - (-32)`
`= -28435/-840 = 5687/168`
`c) -66 × (1/2 - 1/3 + 1/11) + 124 - (-37) + 63 × (-124)`
`= -66 × 17/66 + 124 - (-37) + (-7812)`
`= 17/4356 + 124 - (-37) + (-7812)`
`= -33660083/4356`
3
`a) 3/35 - (3/5 + x) = 2/7`
`3/35 - 3/5 - x = 2/7`
`-x = 2/7 - 3/35 + 3/5`
`-x = 4/5`
`x = -4/5`
`b) 3/7 + 1/7 : x = 3/14`
`4/7 : x = 3/14`
`x = 3/14 × 4/7`
`x = 12/98 = 6/49`