Решите уравнение:

1) (x-12) (3x+9) = 0

2) (x+2) ^2=0

3) x^2+7x=0

4) x^2-25=0

1)

3x^2 + 9x - 36x - 108 = 0

3x^2 - 27x - 108 = 0

x^2 - 9x - 36 = 0

D = 81 + 144 = 225

x1 = (9 + 15) / 2 = 12

x2 = (9 - 15) / 2 = - 3

2)

x + 2 = 0

x = - 2

3)

x (x + 7) = 0

x = 0 или x+7 = 0

x = - 7

4)

(x-5) (x+5) = 0

x-5 = 0 или x+5 = 0

x = 5 x = - 5