Đáp án:
Câu `17:`
`(-1)^3 . (75% - 1/3) : (2 1/4 - 1 1/6)`
`= -1 . (3/4 - 1/3) : (9/4 - 7/6)`
`= -1 . 5/12 : 13/12`
`= -1 . 5/12 . 12/13`
`= (-5)/12 . 12/13`
`= (-5)/13`
$\text{→ Chọn A}$
Câu `18:`
`|x - 1/3| : 2 = (-2)^2 + 4/6`
`=> |x - 1/3| : 2 = 4 + 2/3`
`=> |x - 1/3| : 2 = 14/3`
`=> |x - 1/3| = 14/3 . 2`
`=> |x - 1/3| = 28/3`
`=>` \(\left[ \begin{array}{l}x - 1/3 = 28/3\\x - 1/3 = -28/3\end{array} \right.\) \(\left[ \begin{array}{l}x=2\\x=-1\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x = 29/3\\x=-9\end{array} \right.\) \(\left[ \begin{array}{l}x=2\\x=-1\end{array} \right.\)
$\text{→ Chọn C}$
Câu `19:`
`(x + 1/10)^2 + 5/16 = 14/3 . 3/16`
`=> (x + 1/10)^2 + 5/16 = 14/16`
`=> (x + 1/10)^2 = 14/16 - 5/16`
`=> (x + 1/10)^2 = 9/16`
`=> (x + 1/10)^2 = (3/4)^2`
`=>` \(\left[ \begin{array}{l}x + 1/10 = (-3)/4\\x + 1/10 = 3/4\end{array} \right.\) \(\left[ \begin{array}{l}x=2\\x=-1\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x = (-17)/20/\\x=13/20\end{array} \right.\)
$\text{→ Chọn B}$
