Question

4) x² - 4x + 2x - 7 = 1;

Срочно...​

Answer 1

Ответ:

$-2;\ 4$

Пошаговое объяснение:

$x^2- 4x + 2x - 7 = 1\\\\\ x^{2} - 4x + 2 \; x - 7 - 1 =0\\\\ x^2 - 2x -8 = 0\\\\a=1 ,\ \ b=-2 ,\ \ c=-8\\\\ D = b^2 - 4ac = ( - 2)^2 - 4\cdot1\cdot( - 8) = 4 + 32 = 36\\\\\sqrt{D} =\sqrt{36} = 6\\\\ x_1=\frac{-b-\sqrt{D}}{2a}=\frac{2-6}{2\cdot1}=\frac{-4 }{2 }=-2\\\\ x_2=\frac{-b+\sqrt{D}}{2a}=\frac{2+6}{2\cdot1}=\frac{8}{2}=4$