`(x + 6/7) . (|x| - 1/2) = 0`
`=>` \(\left[ \begin{array}{l}x + \dfrac{6}{7} = 0\\|x| - \dfrac{1}{2} = 0\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x = \dfrac{-6}{7}\\|x| = \dfrac{1}{2}\end{array} \right.\)
`=> x ∈ {(-6)/7 ; 1/2 ; (-1)/2}`
`20% x - x + 1/5 = 3/4`
`=> 1/5 . x - x + 1/5 = 3/4`
`=> x . (1/5 - 1) = 3/4 - 1/5`
`=> x . (-4)/5 = 11/20`
`=> x = 11/20 : (-4)/5`
`=> x = 11/20 . (-5)/4`
`=> x = (-11)/16`
