5x(x^2-4)=0; x=0; x=+-2; y^2(y-1)+4y^2-y-3=0; 4y^2-y-3=(y-1)(4y+3) (y-1)(y2+4y+3)=0; y2+4y+3=(y+1)(y+3); y=1; y=-3; y=-1;