Question

Люди, помогите пожалуйста решить примеры , срочно надо!!​

Answer 1

1) (m+5)² - (m+4)(m-4) = m² + 10m + 25 - (m² - 16) = m² + 10m + 25 - m² + 16 = 10m + 41

2) (3x - 4y)² - (3x + 4y)² = 9x² - 24xy + 16y² - (9x² + 24xy + 16y²) = 9x² - 24xy + 16y² - 9x² - 24xy - 16y² = -48xy

3) (-a - 2b)² + (a - 2b)² = a² + 4ab + 4b² + a² - 4ab + 4b² = 2a² + 8b²

4) (3x - 1)(5x + 4) - 15x² = 17

15x² + 12x - 5x - 4 - 15x² = 17

7x - 4 = 17

7x = 21

x = 3

5) 5 - x(x-3) = (6-x)(x+2)

5 - x² + 3x = 6x + 12 - x² - 2x

-x² + 3x - 6x + x² + 2x = 12 -5

-x = 7

x = -7

6)  -6x² + 7x - 2 = 0

6x² - 7x + 2 = 0

D = 49 - 4·6·2 = 1 > 0 ⇒ 2 корня

x1 = 7 + √1/ 12 = 7+1/12 = 8/12 = 2/3;

x2 = 7 - √1/ 12 = 7 - 1/12 = 6/12 = 1/2 = 0.5

7) 4x² - 4x + 1 = 0

D = 16 - 4·4·1 = 0 ⇒ x1=x2

x1 = 4 + 0/ 8 = 4/8 = 1/2 = 0.5;

x2 = 0.5