Tìm (x), biết:

a) \(5x - {2^3} = {3^3}\)

\(5x - 8 = 27\)

\(5x = 35\)

\(x = 7\)

Vậy \(x = 7\).

b) \(678 + \left( {x - 218} \right) = 541\)

\(x - 218 = 541 - 678\)

\(x - 218 =  - 137\)

\(x =  - 137 + 218\)

\(x = 81\)

Vậy \(x = 81\).

c) \(2\left( {1 - x} \right) + 18 =  - 4\)

\(2\left( {1 - x} \right) =  - 22\)

\(1 - x =  - 11\)

\(x = 1 - \left( { - 11} \right)\)

\(x = 12\).

Vậy \(x = 12\).

d) \({\left( {4x - 11} \right)^6} = {25^3}\)

\({\left( {4x - 11} \right)^6} = {\left( {{5^2}} \right)^3}\)

\({\left( {4x - 11} \right)^6} = {5^6} = {\left( { - 5} \right)^6}\)

Trường hợp 1:

\(4x - 11 = 5\)

\(4x = 16\)

\(x = 4\)

Vậy \(x \in \left\{ {4;1,5} \right\}\).

Trường hợp 2:

\(4x - 11 =  - 5\)

\(4x = 6\)

\(x = 1,5\)