Tìm (x), biết:

a) \(12 + \left( {7 - x} \right) = 18\)

\(7 - x = 18 - 12\)

\(7 - x = 6\)

\(x = 7 - 6\)

\(x = 1\)

Vậy \(x = 1\).

b) \( - 152 - \left( {3x + 1} \right) = 54\)

\[3x + 1 =  - 152 - 54\]

\[3x + 1 =  - 206\]

\(3x =  - 207\)

\(x =  - 69\)

Vậy \(x =  - 69\).

c) \({2^{x + 3}}{.2^2} = {2^2}.3 + 52\)

\({2^{x + 5}} = 4.3 + 52\)

\({2^{x + 5}} = 64\)

\({2^{x + 5}} = {2^6}\)

Suy ra \(x + 5 = 6\)

\(x = 1\)

Vậy \(x = 1\).