Tìm số tự nhiên x, biết: a) 3x - 27 = 4.(3^2). b) 62 - (x + 22) = 2^3.5

a) \(3x - 27 = 4 \cdot {3^2}\)

\(3x - 27 = 4 \cdot 9\)

\(3x - 27 = 36\)

\(3x = 36 + 27\)

\(3x = 63\)

\(x = 21\).

Vậy \(x = 21\).

b) \[62 - \left( {x + 22} \right) = {2^3} \cdot 5\]

\[62 - \left( {x + 22} \right) = 8 \cdot 5\]

\[62 - \left( {x + 22} \right) = 40\]

\[x + 22 = 62 - 40\]

\[x + 22 = 22\]

\[x = 0\].

Vậy \[x = 0\].

c) \(4 \cdot \left( {3{x^3} + {1^{10}}} \right) = 4 \cdot {5^2}\)

\(3{x^3} + {1^{10}} = {5^2}\)

\(3{x^3} + 1 = 25\)

\(3{x^3} = 24\)

\({x^3} = 8\)

\(x = 2\).

Vậy \(x = 2\).