[tex] {x}^{2} + 2x - 3x - 6 - 2( {x}^{2} + 2x \times 5 + 25 = 4x - {x}^{2} [/tex]
[tex] {x}^{2} - x - 6 - 2 {x}^{2} + 10x + 25 = 4x - {x}^{2} [/tex]
[tex] - {x}^{2} + 9x + 19 = 4x - {x}^{2} [/tex]
Adunam x patrat
[tex]9x + 19 = 4x[/tex]
[tex]9x - 4x + 19 = 0[/tex]
[tex]5x + 19 = 0[/tex]
[tex]5x = - 19[/tex]
[tex]x = - \frac{19}{5} [/tex]