Tìm x, biết: 2(3x - 5) + 2(1 - x)= - 4
Giải thích
a) \(2\left( {3x - 5} \right) + 2\left( {1 - x} \right) = - 4\) \(6x - 10 + 2 - 2x = - 4\) \(6x - 2x = 10 - 2 - 4\) \(4x = 4\) \(x = 1\) Vậy \(x = 1\).
| b) \(6x\left( {x + 1} \right) - \left( {2x - 5} \right)\left( {3x + 2} \right) = - 5\) \[\left( {6{x^2} + 6x} \right) - \left( {6{x^2} + 4x - 15x - 10} \right) = - 5\] \[6{x^2} + 6x - 6{x^2} + 11x + 10 = - 5\] \[6{x^2} - 6{x^2} + 6x + 11x = - 10 - 5\] \[17x = - 15\]. \[x = - \frac{{15}}{{17}}\]. Vậy \[x = - \frac{{15}}{{17}}\]. |