Question

Пожалуйста решите уравнение -x^2+6x-7=0

Answer 1

$-x^{2} + 6x - 7 = 0\\x^{2}-6x+7=0\\D=(-6)^{2}-4*7=36-28=8=(2sqrt{2})^{2} \\x_{1}=frac{6-2sqrt{2}}{2}=3-sqrt{2}\\x_{2}=frac{6+2sqrt{2}}{2}=3+sqrt{2}$