A)
x (x - 3) = 0
x = 0
x - 3 = 0 ==> x = 3
b) 4x + x^2 = 0
x (4 + x) = 0
x = 0 ;
4 + x = 0 ==> x = - 4
c) 3x^2 - 8x = 0
x (3x - 8) = 0
x = 0 ;
3x - 8 = 0 ==> 3x = 8 ==> x = 8/3 = 2,(6)
d) y^2 + 6/7*y = 0
y( y + 6/7) = 0
y = 0
y+ 6/7 = 0 ==> y = - 6/7