Tìm giá trị của x , biết: (a) x − 1/6 = x − 5/7 ; (b) 5 x ( 12 x − 7 ) − ( 15 x + 1 ) ( 4 x − 1 ) = − 23

a) \(\frac{{x - 1}}{6} = \frac{{x - 5}}{7}\)

\(7.\left( {x - 1} \right) = 6.\left( {x - 5} \right)\)

\(7x - 7 = 6x - 30\)

\(x = 37\)

Vậy \(x = 37\).

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 \(x = 1\).