`a)` `x^2019 - x = 0` `b)` `-2/3x + 1/3=-1/6`
2 câu trả lời
`x^2019-x=0`
`⇔ x.(x^2018-1)=0`
`⇔ {(x=0),(x^2018-1=0):}`
`⇔ {(x=0),(x^2018=1):}`
`⇔ {(x=0),(x=1),(x=-1):}`
Vậy `x∈{0;1;-1}`
`-2/3.x+1/3=-1/6`
`⇔ -2/3.x=-1/6-1/3`
`⇔ -2/3.x = -1/6-2/6`
`⇔ -2/3.x = -3/6=-1/2`
`⇔ x=(-1)/2:(-2)/3`
`⇔ x=(-1)/2.(-3)/2`
`⇔ x=3/4`
Vậy `x=3/4`
Đáp án:
$\texttt{d.a.r.i}$
`x^2019 - x = 0`
`-> x.(x^2018 - 1) = 0`
`->`\(\left[ \begin{array}{l}x=0\\x^{2018} - 1 = 0\end{array} \right.\)
`->`\(\left[ \begin{array}{l}x=0\\x^{2018} = 1\end{array} \right.\)
`->`\(\left[ \begin{array}{l}x=0\\x = ±1\end{array} \right.\)
Vậy `x ∈ {0; +-1}`
___________________
`-2/3x + 1/3 = -1/6`
`-> -2/3x = -1/6 - 1/3`
`-> -2/3x = -1/2`
`-> x =(-1/2) : (-2/3)`
`-> x = 3/4`
Vậy `x = 3/4`
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