Решите кв. ур - x^2+12x-35=0 y^2+16y+21=0 y^2+y-12=0 y^2-28y+49=0

1) - x^2 + 12 * x - 35 = 0;

x^2 - 12 * x + 35 = 0;

x^2 - 2 * x * 6 + 36 - 36 + 35 = 0;

(x - 6) ^2 - 1 = 0;

(x - 6) ^2 = 1;

x1 - 6 = 1;

x2 - 6 = - 1;

x1 = 7;

x2 = 5.

2) y^2 + 16 * y + 21 = 0;

y^2 + 2 * y * 8 + 64 - 64 + 21 = 0;

(y + 8) ^2 = 43;

y1 + 8 = 43^ (1/2);

y2 + 8 = - 43^ (1/2);

y1 = 43^ (1/2) - 8;

y2 = - 43^ (1/2) - 8.

3) y^2 + y - 12 = 0;

D = 1 + 4 * 12 = 49;

y1 = (-1 - 7) / 2 = - 4;

y2 = (-1 + 7) / 2 = 3.

4) y^2 - 28 * y + 49 = 0;

y^2 - 2 * y * 14 + 196 - 196 + 49 = 0;

(y - 14) ^2 - 147 = 0;

y1 - 14 = 147^ (1/2);

y2 - 14 = - 147^ (1/2);

y1 = 14 + 147^ (1/2);

y2 = 14 - 147^ (1/2).