Đáp án:
1/
` (2x-5) +17 = 6`
` => 2x - 5 = -11`
` 2x = -11+ 5`
` 2x = -6`
` x = -3`
2/
` 10 - 2(4-3x) = -4`
` 10 - 8 + 3x + 4 = 0`
` 3x + 6 = 0`
` 3x = -6`
` x =-2`
3/
`=>` \(\left[ \begin{array}{l}x+12=0\\x-3=0\end{array} \right.\)
`=> \(\left[ \begin{array}{l}x=-12\\x=3\end{array} \right.\)
4/
Ta có ` 8 \vdots x `
` => x ∈ { -8 ; - 4 ; - 2; -1 ; 1 ; 2 ;4; 8}`
` 12 \vdots x`
` => x ∈ { -12 ; - 6; - 4 ; -3 ; -2 ; -1 ; 1 ; 2 ;3 ; ; 4 ;6 ; 12}`
` => x ∈ { -4; -2 ; -1 ; 1 ; 2 ; 4}`
5/
Ta có
`BCNN ( 4;6) = 12`
` => X ∈ { 12; 24 ; 36 ; 48 ; 60; 72; 84 ; 96 ;108; ...}`
Mà ` 50 < x <100`
` => x ∈ { 60; 72; 84 ; 96 }`
