a)
x 2 + 3 x = 0
<=> x ( x + 3 ) = 0
<=> x = 0 oder x = - 3
b)
- 6 x + 2 x 2 = 0
<=> 2 x ( - 3 + x ) = 0
<=> 2 x = 0 oder - 3 + x = 0
<=> x = 0 oder x = 3
c)
( 4 / 5 ) x - ( 1 / 2 ) x 2 = 0
<=> ( 8 / 10 ) x - ( 5 / 10 ) x 2 = 0
<=> ( 1 / 10 ) x * ( 8 - 5 x ) = 0
<=> x = ( 1 / 10 ) x = 0 oder 8 - 5 x = 0
<=> x = 0 oder 8 = 5 x
<=> x = 0 oder x = 8 / 5