Question

9 sqrt{x - 1}=x^2 sqrt{x - 1}

Answer 1

$9 \sqrt{x - 1}=x^2 \sqrt{x - 1}$

D:

$x \ge 1$

$x^2 \sqrt{x - 1}-9 \sqrt{x - 1}=0$

$\sqrt{x - 1}(x^2-9)=0$

$\sqrt{x - 1}(x-3)(x+3)=0$

$\sqrt{x - 1}=0\ \ \ \ \ x-3=0\ \ \ \ \ x+3=0$

$x=1\ \ \ \ \ x=3\ \ \ \ \ x=-3<1$

Ответ

x=1,x=3