If the equation `4x^2+hxy+y^2=0` represent coincident lines, then h is equal to

If the equation x^(2)+2hxy+2fy+c=0 represents a pair of lines, then

The equation x^(2)+ky^(2)+4xy=0 represents two coincident lines if k=

The equation x^(2)+ky^(2)+4xy=0 represents two coincident lines if k=

The equation 4x^(2)+hxy+y^(2)=0 represents a pair of coincident lines through origin, if h=

If the equation 2x^2-2hxy+2y^2=0 represents two coincident straight lines passing through the origin , then h is equal to

The equation ax^(2)+2hxy+ay^(2)=0 represents a pair of coincident lines through origin, if

If the equation given by hxy+10x+6y+4=0 represents a pair of lines, then h is equal to