Câu 1:
a) `31/17 + -5/13 + -8/13 - 14/17`
= `31/17 - 14/17 + -5/13 + -8/13`
= 1 + -1
= 0
b) `7 5/11` - `(2 3/7 + 3 5/11)`
= `7 5/11 - 2 3/7 - 3 5/11`
= `82/11 - 17/7 - 38/11`
= `82/11 - 38/11 - 17/7`
= `4 - 17/7`
=`11/7`
c) `(5/7 . 0,6 - 5 : 3 1/2)` . (40% - 1,4) . `(-2)^3`
= `(5/7 . 3/5 - 5 : 7/2)` . `(2/5 - 7/5)` . -8
= `(3/7 - 10/7)` . -1 . -8
= -1.-1.-8
= -8
Câu 2: Tìm x, biết
a) `x + 1/2` = `-3/4`
`x` = `-3/4 - 1/2`
`x` = `-5/4`
b) `(x+3)^3` = 8
`(x+3)^3 = `2^3`
`=>` `x + 3` = 2
`x` = 2 - 3 = -1
Vậy `x` = -1
c) 3. |`x`| - `1/3` = `8/3`
3. |`x`| = `8/3 + 1/3' = `9/3` = 3
|`x`| = 3 : 3 = 1
Vậy x = \(\left[ \begin{array}{l}x=1\\x=-1\end{array} \right.\)
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