Bài $3$ :
$b)$
`-3x +37 = (-4)^2`
`=> -3x + 37 = 16`
`=> -3x = -21`
`=> x = 7`
$c)$
`|2x + 7| = 5`
\(\left[ \begin{array}{l}2x +7 =5\\2x + 7 = -5\end{array} \right.\)
\(\left[ \begin{array}{l}x = -1\\x = -6\end{array} \right.\)
Vậy `x \in {-1 ; -6}`
$d)$
`-x +21 = 15 +2x`
`=> -x - 2x = 15 - 21`
`=> -3x = -6`
`=> x = 2`
$e)$
`5^{4x} : 5^5 = 5^{2022} : 5^{2019}`
`=>5^{4x} = 5^{2022} : 5^{2019} . 5^5`
`=>5^{4x} = 5^{2022 - 2019 +5}`
`=>5^{4x} =5^8`
`=>4x = 8`
`=> x = 2`
$f)$
`(x-1)^3 + 2 = |-66|`
`=> (x-1)^3 = 66 - 2`
`=> (x-1)^3 = 64`
`=> (x-1)^3 = 4^3`
`=> x-1 = 4`
`=> x = 3`
