Решить квадратные уравнения 7x^2-4x+4=0 3x^2+7x+2=0 9x^2-12x+4=0 x^2-3x-10=0

7х^2 - 4x+4=0
D=(-4)-4*7*4=16-112=-96
Нет решений

$3x {}^{2} + 7x + 2 = 0 \\ 3x {}^{2} + 6x + x + 2 = 0 \\ 3x(x + 2) + x + 2 = 0 \\ (x + 2)(3x + 1) = 0 \\x + 2 = 0 \\ 3x + 1 = 0 \\ x1 = - 2 \\ x2 = - \frac {1}{3}$

$9x {}^{2} - 12x + 4 = 0 \\ (3x - 2) {}^{2} = 0 \\ 3x - 2 = 0 \\ 3x = 2 \\ x = \frac{2}{3}$

$x {}^{2} - 3x - 10 = 0 \\ x {}^{2} + 2x - 5x - 10 = 0 \\ x(x + 2) - 5(x + 2) = 0 \\ (x + 2)(x - 5) = 0 \\ x + 2 = 0 \\ x - 5 = 0 \\ x1 = - 2 \\ x2 = 5$