-х^2-4х+9=0 Помогите

-x² - 4x + 9 = 0 D = b² - 4ac D = (-4)² - 4 * (-1) * 9 = 52 [latex] x_{1,2} = \frac{-bб \sqrt{D} }{2a} [/latex] [latex] x_{1,2} = \frac{4б \sqrt{52} }{-2} [/latex]  [latex] x_{1,2} = \frac{4б2 \sqrt{13} }{-2} [/latex] [latex] x_{1,2} = \frac{2(2б \sqrt{13} }{-2} [/latex] [latex] x_{1,2} = -1 * (2 б \sqrt{13}) [/latex] [latex] x_{1} = -2 - \sqrt{13} ; x_{2} = -2+ \sqrt{13} [/latex]