а) -4( x + 3) = 0 |:-4
x+3=0
x=-3
-4(-3+3)=-4*0=0
б) -5y( y - 2)( y + 9) = 0 | :5
y( y - 2)( y + 9) = 0
y=0:
0(0-2)(0+9)=0*(-2)*9=0
y=2:
2(2-2)(2+9)=2*0*11=0
y=-9:
-9(-9-2)(-9+9)=9*11*0=0