Tìm giá trị của x , biết: (a) 2 x + 7/3 = 3/2 ; (b) 5 x ( 12 x − 7 ) − ( 15 x + 1 ) ( 4 x − 1 ) = − 23 .

a) \(\frac{{2x + 7}}{3} = \frac{3}{2}\)

\(2.\left( {2x + 7} \right) = 3.3\)

\(4x + 14 = 9\)

\(4x = - 5\)

\(x = - \frac{5}{4}\)

Vậy \(x = - \frac{5}{4}\).

b) \(5x\left( {12x - 7} \right) - \left( {15x + 1} \right)\left( {4x - 1} \right) = - 23\)

\(60{x^2} - 35x - \left( {60{x^2} - 15x + 4x - 1} \right) = - 23\)

\(60{x^2} - 35x - 60{x^2} + 15x - 4x + 1 = - 23\)

\( - 24x = - 24\)

\(x = 1\)

Vậy \(x = 1\).