Question

Решите уравнение x^2-4x -1 = 3 x-1 9-x^2

Answer 1

$x^2-4x-1=3 \\ x^2-4x-4=0 \\ D=16+16=32=(4 \sqrt{2})^2 \\ x_1= \frac{4+4 \sqrt{2} }{2}(:2)=2+2 \sqrt{2} \\ x_2=2-2 \sqrt{2}$

$(x-1)(9-x^2)=0 \\ \\ x-1=0 \\ x=1 \\ \\ 9-x^2=0 \\ x^2=9 \\ x=\pm3$
ОТВЕТ: x=1; x=-3; x=3