√(x-1)+3=x (под корнем x-1)

1.
$\sqrt{x - 1} = x - 3$
2. х - 1 = х² - 6х + 9
3. х - 1 - х² + 6х - 9 = 0
4. 7х - 10 - х² = 0
5. - х² + 7х - 10 = 0
6.
$x = \frac{ - ( - 7) + - \sqrt{( - 7 {)}^{2} - 4 \times 1 \times 10} }{?}$
7.
$x = \frac{7 + - \sqrt{49 - 40} }{2}$
8.
$x = \frac{7 + - 3}{2}$
9.
$x = \frac{7 + 3}{ 2} \\ x = \frac{7 - 3}{2}$
10.
$x = 5 \\ x = 2$
11.
$\sqrt{5 - 1} + 3 = 5 \\ \sqrt{2 - 1} + 3 = 2$
12.
$5 = 5 \\ 4 = 2$
13. x = 5;
x ≠ 2.

Ответ: 5