Ха
Хариша
a)
4x^2 + 6x = 9x^2 - 15x
4x^2 - 9x^2 + 6x + 15x = 0
-5x^2 + 21x = 0
5x^2 - 21x = 0
x * (5x - 21) = 0
x1 = 0
5x - 21 = 0
x2 = 21/5
x2 = 4,2
Ответ: x1 = 0; x2 = 4,2
b)
12x + 6x^2 = 5x^2 - 7x
12x +7x + 6x^2 - 5x^2 = 0
19x + x^2 = 0
x(19 + x) = 0
x1 = 0
19 + x = 0
x2 = -19
Ответ: x1 = 0; x2 = -19