`a)3/(35)-(3/5+x)=2/7`
`3/5+x=3/(35)-2/7`
`3/5+x=3/(35)-10/35`
`3/5+x=-7/(35)`
`3/5+x=-1/5`
`x=(-1/5)-3/5`
`x=-4/5`
Vậy `x=-4/5`
`b)(5x-3/8).(1/2x+7/4)=0`
`⇒`\(\left[ \begin{array}{l}5x-\dfrac{3}{8}=0\\\dfrac{1}{2}x+\dfrac{7}{4}=0\end{array} \right.\)
`⇒`\(\left[ \begin{array}{l}5x=0+\dfrac{3}{8}\\\dfrac{1}{2}x=0-\dfrac{7}{4}\end{array} \right.\)
`⇒`\(\left[ \begin{array}{l}5x=\dfrac{3}{8}\\\dfrac{1}{2}x=\dfrac{-7}{4}\end{array} \right.\)
`⇒`\(\left[ \begin{array}{l}x=\dfrac{3}{8} : 5\\x=\dfrac{-7}{4} : \dfrac{1}{2}\end{array} \right.\)
`⇒`\(\left[ \begin{array}{l}x=\dfrac{3}{40}\\x=\dfrac{-7}{2}\end{array} \right.\)
Vậy `x=3/(40)` hoặc `x=-7/2`
`c)3/7+1/7 : x=3/(14)`
`1/7 : x=3/(14) - 3/7`
`1/7 : x=3/(14)-6/(14)`
`1/7 : x=-3/(14)`
`x=1/7 : (-3/14)`
`x=1/7 . (-14/3)`
`x=-2/3`
Vậy `x=-2/3`
`d)45/27 - x . 1/8=3/5`
`x . 1/8=45/27-3/5`
`x . 1/8=5/3 - 3/5`
`x . 1/8=25/15-9/(15)`
`x . 1/8=16/15`
`x=16/15 : 1/8`
`x=(128)/(15)`
Vậy `x=(128)/(15)`
`e)|x-3/5|=7/4`
`⇒`\(\left[ \begin{array}{l}x-\dfrac{3}{5}=\dfrac{7}{4}\\x-\dfrac{3}{5}=\dfrac{-7}{4}\end{array} \right.\)
`⇒`\(\left[ \begin{array}{l}x=\dfrac{7}{4}+\dfrac{3}{5}\\x=\dfrac{-7}{4}+\dfrac{3}{5}\end{array} \right.\)
`⇒`\(\left[ \begin{array}{l}x=\dfrac{47}{20}\\x=\dfrac{-23}{20}\end{array} \right.\)
Vậy `x=47/20` hoặc `x=-23/20`
