Tìm x, biết: 3 (2x - 3)+ 2 (2 - x) = - 3
Giải thích
a) \(3\left( {2x - 3} \right) + 2\left( {2 - x} \right) = - 3\) \(6x - 9 + 4 - 2x = - 3\) \(6x - 2x = 9 - 4 - 3\) \(4x = 2\) \(x = \frac{1}{2}\). Vậy \(x = \frac{1}{2}\). | b) \(3x\left( {2x + 3} \right) - \left( {2x + 5} \right)\left( {3x - 2} \right) = 8\) \(6{x^2} + 9x - \left( {6{x^2} - 4x + 15x - 10} \right) = 8\) \(6{x^2} + 9x - 6{x^2} + 4x - 15x + 10 = 8\) \(\left( {6{x^2} - 6{x^2}} \right) + \left( {9x + 4x - 15x} \right) = 8 - 10\) \( - 2x = - 2\) \(x = 1\) Vậy \(x = 1\). |