Tìm (x), biết:

a) \(8 - 2x =  - 4\)

\(2x = 8 - \left( { - 4} \right)\)

\(2x = 12\)

\(x = 6\)

Vậy \(x = 6\).

b) \(255 - \left( {x + 9} \right) = 184\)

\(x + 9 = 255 - 184\)

\(x + 9 = 71\)

\(x = 71 - 9\)

\(x = 62\)

Vậy \(x = 62\).

c) \(2\left( {x - 17} \right) = 289 - \left( {36 + 289} \right)\)

\(2\left( {x - 17} \right) = 289 - 36 - 289\)

\(2\left( {x - 17} \right) =  - 36\)

\(x - 17 =  - 18\)

\(x =  - 1\)

Vậy \(x =  - 1\).

d) \(\left[ {{{\left( {x + 3} \right)}^2} - 8} \right].2 =  - 14\)

\({\left( {x + 3} \right)^2} - 8 =  - 7\)

\({\left( {x + 3} \right)^2} = 1\)

Trường hợp 1:

\(x + 3 = 1\)

\(x =  - 2\)

Vậy \(x \in \left\{ { - 2; - 4} \right\}\).

Trường hợp 1:

\(x + 3 =  - 1\)

\(x =  - 4\)