Question

1)2х^2+3х+4=0 2)9х^2-6х+1=0

Answer 1

2x^2 + 3x + 4 = 0;
       D = b^2 - 4ac;
D = 3^2 - 4 * 2 * 4;
D = 9 - 32 = -23;
D < 0, корней нет!
       Ответ: x ∈ Ø.

9x^2 - 6x + 1 = 0;
       D = b^2 - 4ac;
D = -6^2 - 4 * 9 * 1;
D = 36 - 36 = 0;
D = 0, один корень!
       x = -b/2a;
x = 6/(2*9);
x = 6/18;  |:6
x = 1/3;
       Ответ: 1/3.