`a) ( -4/5 + 4/3) + (-5/4 + 14/5) - 7/3`
`= -4/5+ 4/3 + \frac{-5}{4} + 14/5 - 7/3`
`= ( -4/5 + 14/5) + ( 4/3 - 7/3) + \frac{-5}{4} `
`= 2 + (-1 )+ \frac{-5}{4} `
`= 1 + \frac{-5}{4} `
`= -1/4`
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`b)1/3 . 4/5 + 1/3 . 6/5 - 4/3`
`= 1/3 . ( 4/5 + 6/5) - 4/3`
`= 1/3 . 2 - 4/3`
`= 2/3 - 4/3`
`= -2/3`
------------------------------------------------
`c) 4/19 . \frac{-3}{7}+ \frac{-3}{7} . 15/19 + 5/7`
`= \frac{-3}{7} . ( 4/19 + 15/19) + 5/7`
`= \frac{-3}{7} . 1 + 5/7`
`= \frac{-3}{7} + 5/7`
`= 2/7`
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`d) \frac{-5}{7} + \frac{-5}{7} + \frac{-5}{7} + \frac{9}{14} + 1 5/7`
`= -10/14 + \frac{-10}{14}+ \frac{-10}{14}+ \frac{9}{14} + 24/14`
`= \frac{-10 + (-10) + (-10) + 9 + 24}{14}`
`= 3/14`
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`e) ( -2/3)^2 - (-3)^0 + 5/18`
`= 4/9 - 1 + 5/18`
`= 8/18 - 18/18 + 5/18`
`= \frac{8-18+5}{18}`
`= -5/18`
-------------------------------------------
Bài 2)
`a) 2/3 . x + 1/4 = 7/12`
`2/3 . x = 7/12 - 1/4`
`2/3 x = 1/3`
`x = 1/3 : 2/3`
`x = 1/2`
-------------------------------------------
`b) 1/3 + 2/5 ( x + 1) = 1`
`2/5 ( x + 1) = 1 - 1/3`
`2/5 ( x + 1) = 2/3`
`( x + 1) = 2/3 : 2/5`
`x + 1 = 5/3`
`x = 5/3 - 1`
`x = 2/3`
----------------------------------------------
`c) 1/4 + 1/3 : 3 x = -5`
`1/3 : 3x = -5 - 1/4`
`1/3 : 3x = -21/4`
`3x = 1/3 : (-21/4)`
`3x = -4/63`
`x = -4/63 : 3`
`x = -4/189`
