a) -3/7 . 2/19 + -3/7 . 17/19 – 4/7
b) 4/5 . 3/5 . ( -2/3 + 3)
c) 4/3 . (1/2 + 7/4)+ 7/4
d) (-3/4 + 5/2) + 5/2
g) -2/9 . 5/2 – -1/6 ÷ 3/7 + 17/8
h) -5/14 + -9/14 . [(-2/3)³ ÷ (-1/3)²]
Bài 2
a) 5/6 + x = -1/8
b) x – -5/3 = -7/5
c) -1/2 – ( x + 3/4) = -5/4
d) -3/5x + -7/4 = 3/10
Đáp án:
Giải thích các bước giải:
$ -3/7 . 2/19 + -3/7 . 17/19 – 4/7 = -1 $
` 4/5 . 3/5 . ( -2/3 + 3) = 28/25 `
` 4/3 . (1/2 + 7/4)+ 7/4 = 19/4 `
`(-3/4 + 5/2) + 5/2 = 17/4 `
` -2/9 . 5/2 – -1/6 ÷ 3/7 + 17/8 = 47/24 `
` -5/14 + -9/14 . [(-2/3)³ ÷ (-1/3)²] = -41/14 `
` 5/6 + x = -1/8`
`x = 5/6 – ( – 1/8 ) `
`x = 23/24 `
` x – -5/3 = -7/5 `
`x = – 7/5 + (-5/3 ) `
`x = -46/15 `
`-1/2 – ( x + 3/4) = -5/4`
`x + 3/4 = -1/2 – ( -5/4 ) = 3/4 `
`x = 3/4 – 3/4 `
`x = 0 `
` -3/5x + -7/4 = 3/10`
`-3/5 x = 3/10 – ( – 7/4 ) `
`-3/5x = 41/20`
`x = 41/20 : -3 / 5 `
`x -41/12 `
Đáp án + giải thích bước giải :
Bài 1
`a) -3/7 . 2/19 + (-3/7) . 17/19 – 4/7`
`= -3/7 . (2/19 + 17/19) – 4/7`
`= -3/7 . 1 – 4/7`
`= -3/7 – 4/7`
`= -1`
`b) 4/5 . 3/5 . (-2/3 + 3)`
`= 12/25 . 7/3`
`= 28/25`
`c) 4/3 . (1/2 + 7/4) + 7/4`
`= 4/3 . 9/4 + 7/4`
`= 1/3 + 7/4`
`= 25/12`
`d) (-3/4 + 5/2) + 5/2`
`= 7/4 + 5/2`
`= 17/4`
`g) -2/9 . 5/2 – (-1/6) : 3/7 + 17/9`
`= -5/9 – (-7/18) + 17/9`
`= -1/6 + 17/9`
`= 31/18`
`h) -5/14 + (-9/14) . [(-2/3)^3 : (-1/3)^2]`
`= -5/14 + (-9/14) . 4`
`= -5/14 + (-18/7)`
`= -41/14`
Bài 2
`a) 5/6 + x = -1/8`
`-> x = -23/24`
`b) x – (-5/3) = -7/5`
`-> x + 5/3 = -7/5`
`-> x = -46/15`
`c) -1/2 – (x + 3/4) = -5/4`
`-> x + 3/4 = 3/4`
`-> x = 0`
`d) -3/5x + (-7/4) = 3/10`
`-> -3/5x = 41/20`
`-> x = -41/12`