Tìm x , biết: (a) 1/ 4 x − 1/ 3 = − 5/ 9

a) \(\frac{1}{4}x - \frac{1}{3} = - \frac{5}{9}\)

\(\frac{1}{4}x = - \frac{5}{9} + \frac{1}{3}\)

\(\frac{1}{4}x = - \frac{2}{9}\)

\(x = - \frac{2}{9}:\frac{1}{4}\)

\(x = - \frac{8}{9}\)

Vậy \(x = - \frac{8}{9}\).

b) \({2^{x - 3}} - {3.2^x} = - 92\)

\(\frac{{{2^x}}}{{{2^3}}} - {3.2^x} = - 92\)

\({2^x}.\left( {\frac{1}{8} - 3} \right) = - 92\)

\({2^x}.\frac{{ - 23}}{8} = - 92\)

\({2^x} = 32\)

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

Suy ra \(x = 5\)

Vậy \(x = 5\).