E= { x thuộc R l ( x^2 – 10x + 21 ) ( x^3 – x ) = 0 25/07/2021 Bởi Lydia E= { x thuộc R l ( x^2 – 10x + 21 ) ( x^3 – x ) = 0
`(x^2 – 10x + 21)(x^3 – x) = 0` `<=>(x^2-3x-7x+21)(x^2-1)=0` `<=>x(x-7)(x-3)(x^2-1)=0` `<=>(x(x-7)(x-3)(x-1)(x+1)=0` `⇔` \(\left[ \begin{array}{l}x=0\\x-7=0\\x-3=0\\x-1=0\\x+1=0\end{array} \right.\) `⇔` \(\left[ \begin{array}{l}x=0\\x=7\\x=3\\x=1\\x=-1\end{array} \right.\) `⇔ E = {0;7;3;1;-1}` Xin hay nhất ! Bình luận
`(x^2 – 10x + 21)(x^3 – x) = 0`
`<=>(x^2-3x-7x+21)(x^2-1)=0`
`<=>x(x-7)(x-3)(x^2-1)=0`
`<=>(x(x-7)(x-3)(x-1)(x+1)=0`
`⇔` \(\left[ \begin{array}{l}x=0\\x-7=0\\x-3=0\\x-1=0\\x+1=0\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x=0\\x=7\\x=3\\x=1\\x=-1\end{array} \right.\)
`⇔ E = {0;7;3;1;-1}`
Xin hay nhất !
Đáp án:
Giải thích các bước giải:
`x^2-10x+21=0`
`x^3-x=0`
`⇒ E={7;3;0;-1;1}`