с решением уравнений по алгебре. Зарание

1 ) (x-1)(x+2)=0

x-1 = 0  ; x + 2 = 0 ;

x = 1 ; x = -2

2) (2a+7)(a-5) = 0

2a + 7 = 0  ; a - 5 = 0;

a = -7/2 = -3,5 ; a = 5 ;

3) -3x(0,4x-12)=0

-3x = 0 ; 0,4x-12=0;

x =0 ; x = 30

4) (3x-5)(x+3)(x-4)=0

3x-5 =0 ; x +3 =0 ; x -4 =0

x = 5/3 ; x = -3 ;x =4

5) 5x(x+1)(3x-19) = 0

5x = 0 ; x+1 = 0 ; 3x-19 = 0

x = 0 ; x = -1 ; x =19/3;

6)x^4 = 0

x = 0

7) (2+3x)^2=0

2 + 3x =0 ;

x = -2/3;

8) x^2 - 4x = 0

x(x-4) = 0

x = 0 ; x = 4 ;

9) x^3-3x^2 = 0 ;

x^2(x-3)=0

x = 0 ; x = 3 ;

10) z^2-9=0

z = 3 ;

11) x^3 - 4x = 0

x(x^2-4) = 0

x = 0 ; x = 2 ; x = -2

12) x^2 + 4x + 4 = 0

D = 16 - 16 = 0 ;

x =