1) Решите уравнение: а) - x2+3x=0 б) 7x-x2=0 в) - x2+7x=0 г) 19x-x2=0 2) а) x2+10x+25=0 б) 4x2-8x+4=0

1)

а)

-x^2 + 3x = 0; x^2 - 3x = 0; x (x - 3) = 0; [x = 0;

[x - 3 = 0; [x = 0;

[x = 3.

б)

7x - x^2 = 0; x^2 - 7x = 0; x (x - 7) = 0; [x = 0;

[x - 7 = 0; [x = 0;

[x = 7.

в)

x^2 + 7x = 0; x^2 - 7x = 0; x (x - 7) = 0; [x = 0;

[x - 7 = 0; [x = 0;

[x = 7.

г)

19x - x^2 = 0; x^2 - 19x = 0; x (x - 19) = 0; [x = 0;

[x - 19 = 0; [x = 0;

[x = 19.

2)

а)

x^2 + 10x + 25 = 0; (x + 5) ^2 = 0; x + 5 = 0; x = - 5.

б)

4x^2 - 8x + 4 = 0; (2x - 2) ^2 = 0; 2x - 2 = 0; 2x = 2; x = 1.

Ответ:

1)

а) 0; 3. б) 0; 7; в) 0; 7; г) 0; 19.

2)

а) - 5. б) 1.