Question

помогите пожалуйста​

Answer 1

1) (х + 2)² = 2х + 3
х² + 4х + 4 = 2х + 3
х² + 4х + 4 - 2х - 3 = 0
х² + 2х + 1 = 0
(х + 1)² = 0
х + 1 = 0
х = -1
Ответ: -1.

2) 5(х - 2)² = 3х - 6
5(х² - 4х + 4) - 3х + 6 = 0
5х² - 20х + 20 - 3х + 6 = 0
5х² - 23х + 26 = 0
D = 23² - 4•5•26 = 529 - 520 = 9
√D =√9 = 3
х1 = (23 + 3) / (2•5) = 26/10 = 2,6
х2 = (23 - 3) / (2•5) = 20/10 = 2
Ответ: 2,6; 2.

3) (х + 2)(х - 3) = 2х(х - 4) + 6
х² + 2х - 3х - 6 = 2х² - 8х + 6
2х² - 8х + 6 - х² - 2х + 3х + 6 = 0
х² - 7х + 12 = 0
D = 7² - 4•12 = 49 - 48 = 1
√D =√1 = 1
х1 = (7 + 1)/2 = 8/2 = 4
х2 = (7 - 1)/2 = 6/2 = 3
Ответ: 4; 3.

4) х(х - 1) - (х - 3)(х + 3) = (х + 2)² - 1
х² - х - (х²- 9) - (х² + 4х + 4) + 1 = 0
х² - х - х² + 9 - х² - 4х - 4 + 1 = 0
-х² - 5х + 6 = 0
х² + 5х - 6 = 0
D = 5² - 4 • (-6) = 25 + 24 = 49
√D =√49 = 7
х1 = (-5 + 7)/2 = 2/2 = 1
х2 = (-5 - 7)/2 = -12/2 = -6
Ответ: 1; -6.