Đáp án:
a) `x in { 13/8 ; -5/8 }`
b) `x = -13/6`
Giải thích các bước giải:
a) `| 2x - 1 | = 9/4`
`to` \(\left[ \begin{array}{l}2x-1=\dfrac{9}{4}\\2x-1=-\dfrac{9}{4}\end{array} \right.\) `to` \(\left[ \begin{array}{l}2x=\dfrac{9}{4}+1\\2x=-\dfrac{9}{4}+1\end{array} \right.\)
`to`\(\left[ \begin{array}{l}2x=\dfrac{13}{4}\\2x=-\dfrac{5}{4}\end{array} \right.\) `to` \(\left[ \begin{array}{l}x=\dfrac{13}{8}\\x=-\dfrac{5}{8}\end{array} \right.\)
Vậy `x in { 13/8 ; -5/8 }`
b) `x/4 + 9/8 = 7/12`
`to x/4 = 7/12 - 9/8`
`to x/4 = -13/24`
`to (6x)/24 = -13/24`
`to 6x = -13`
`to x = -13/6`
Vậy `x = -13/6`
