`a)(3x-1)^2-24=25`
`(3x-1)^2=49`
\(\left[ \begin{array}{l}(3x-1)^2=7^2\\(3x-1)^2=(-7)^2\end{array} \right.\)
\(\left[ \begin{array}{l}3x-1=7 \\3x-1=-7\end{array} \right.\)
\(\left[ \begin{array}{l}3x=8 \\3x=-8 \end{array} \right.\)
\(\left[ \begin{array}{l}x=8:3=8/3\\x=-8:3=-8/3\end{array} \right.\)
Vậy `x∈{±8/3}`
`c)1/3.-2/5=2/3.(x-1)`
`-2/15=2/3.(x-1)`
`x-1=-2/15:2/3`
`x-1=2/5`
`x=2/5+1`
`x=7/5`
`d)2/3+1/3:3x=20%`
`1/3:2x=20%-2/3`
`1/3:2x=-7/15`
`2x=1/3:-7/15`
`2x=-5/7`
`x=-5/7:2`
`x=-5/14`