Question

Решите уравнение (5х – 7)(8х + 1) = (7 – 5х)

Answer 1

Ответ:

Объяснение:

$40x^2 + 5x - 56x - 7 = 7-5x\\40x^2 + 5x - 56x - 7 - 7+5x = 0\\40x^2-46x-14 = 0 | :2\\20x^2 - 23x -7 = 0\\D = 529 + 560 = 33^2\\x1 = (23 + 33)/40 = 1.4\\x2 = (23-33)/40 = -0.25$

Answer 2

Ответ:

x₁ = 1.4

x₂ = 2.8

x₃ = 0.75

Объяснение:

(5х – 7)(8х + 1) = (7 – 5х)

(5х – 7)(8х + 1) = 7 - 5x

5x(5х – 7)(8х + 1) = 7

5x = 7;         5x - 7 = 7;      8x + 1 = 7

x = 1.4;         5x = 14;          8x = 6

                   x = 2.8;           x = 0.75