Решите уравнения: 1) (5-y) ^2+17 = (y-3) ^2

2) 7x+x (x-7) = (2x+5) (5-2x)

1) (5 - y) ² + 17 = (y - 3) ²

(5 - y) (5 - y) + 17 = (y - 3) (y - 3)

25 - 5y - 5y + y² + 17 = y² - 3y - 3y + 9

y² - 10y + 42 = y² - 6y + 9

y² - 10y - y² + 6y = 9 - 42

- 4y = - 33

4y = 33

y = 33/4

y = 8,25

2) 7x + x (x - 7) = (2x + 5) (5 - 2x)

7x + x² - 7x = 10x - 4x² + 25 - 10x

x² = - 4x² + 25

x² + 4x² - 25 = 0

5x² - 25 = 0

D = b² - 4ac

D = 0² - 4 * 5 * (- 25) = 0 + 500 = 500

x₁ = 0 + √500 / 10 = 10√5 / 10 = √5

x₂ = 0 - √ 500 / 10 = - 10√5 / 10 = - √5