Tìm (x), biết:

a) \(\left( {454 - x} \right) + {4^3} = 116\)

\(\left( {454 - x} \right) + 64 = 116\)

\(454 - x = 52\)

\(x = 402\)

Vậy \(x = 402\).

b) \(42x + 168 = 84\)

\(42x =  - 84\)

\(x =  - 2\)

Vậy \(x =  - 2\).

c) \[18 - \left( {x + 14} \right)\,\,{\rm{:}}\,\,{\rm{3  =  27}}\]

\(\left( {x + 14} \right):3 =  - 9\)

\(x + 14 =  - 27\)

\(x =  - 41\)

Vậy \(x =  - 41\).

d) \({\left( {x - 1} \right)^4} = 16\)

\({\left( {x - 1} \right)^4} = {2^4} = {\left( { - 2} \right)^4}\)

Trường hợp 1:

\(x - 1 = 2\)

\(x = 2 + 1\)

\(x = 3\)

Vậy \(x \in \left\{ {3; - 1} \right\}\).

Trường hợp 2:

\(x - 1 =  - 2\) \(96 = {2^5}.3\)

\(x =  - 2 + 1\)

\(x =  - 1\)