Решите уравнение: 1. (x-1)(x-2)+(x+3)(x-3)+3x+18=0 - вопрос №923504411233318023525560 от valery2905 22.04.2020 07:48

Question

Математика: Решите уравнение: 1. (x-1)(x-2)+(x+3)(x-3)+3x+18=0 2. (3x-5)^2-5(5-6x)=0 3. (x-7)^2+7(2x-14)=0

valery2905 · Answer

(x - 1)(x - 2) + (x + 3)(x - 3) + 3x + 18 = 0
x² - 2x - x + 2 + x² - 9 + 3x + 18 = 0
2x² + 11 = 0
2x² = -11
x∉R

(3x - 5)² - 5(5 - 6x) = 0
9x² - 30x + 25 - 25 + 30x = 0
9x² = 0
x = 0

(x - 7)² + 7(2x - 14) = 0
(x - 7)² + 14(x - 7) = 0
(x - 7)(x - 7 + 14) = 0
(x - 7)(x + 7) = 0
x = ± 7