`|x + 4| . |x| = 0`
`=>` \(\left[ \begin{array}{l}|x + 4| = 0\\|x| = 0\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x + 4 = 0\\x=0\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=-4\\x=0\end{array} \right.\)
`--`
`x^2 = 4`
`=>` \(\left[ \begin{array}{l}x^2 = (-2)^2\\x^2 = 2^2\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x = -2\\x^2 = 2\end{array} \right.\)
`--`
`1 + 2 + 3 + 4 + ... + 100 + x = 5050`
`=> (x + 1) . [(x - 1) : 1 + 1] : 2 = 5050`
`=> (x + 1) . x : 2 = 5050`
`=> (x + 1) . x = 5050 . 2`
`=> (x + 1) . x = 10100`
`=> (x + 1) . x = 101 . 100`
`=> x = 100`
`--`
`|2x + 4| = 16`
`=>` \(\left[ \begin{array}{l}2x + 4 = 16\\2x + 4 = -16\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}2x = 12\\2x=-20\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=6\\x=-10\end{array} \right.\)
`--`
`(2^4 - 4^2) . 100! + 2020 = x`
`=> (16 - 16) . 100! + 2020 = x`
`=> 0 . (1 . 2 . 3 . ... . 100) + 2020 = x`
`=> 0 + 2020 = x`
`=> x = 2020`
`--`
`3x + 24 = |85% - 0,85|`
`=> 3x + 24 = |0,85 - 0,85|`
`=> 3x + 24 = 0`
`=> 3x = 0 - 24`
`=> 3x = -24`
`=> x = -24 : 3`
`=> x = -8`
