Question

Помогите решить 9 x^2 - (7x-2)(x+3) = -12x + 1

Answer 1

9x^2 - (7x-2)(x+3) = 9x^2 - 7x^2 - 21x + 2x +6 = 2x^2 - 19x + 6
2x^2 -19x + 6 = -12x+1
2x^2 -19x +12x + 6 -1 = 0
2x^2 -7x + 5 = 0
D = 7*7 - 4*2*5 = 49 - 40 = 9 = 3^2
x1 = (7 - 3) / (2*2) = 4 / 4 = 1
x2 = (7 + 3) / (2*2) = 10/4 = 5/2 = 2.5
Ответ: 1 и 2.5

Answer 2

спасибо добрый человек