If the equation `kx^2-2xy-y^2-2x+2y=0` represents a pair of lines , then k is equal to

If the equation 2x^2-2xy-y^2-6x+6y+c=0 represents a pair of lines then c=

If the equation 2x^(2)+7xy+3y^(2)-9x-7y+k=0 represents a pair of lines, then k is equal to

If the equation 2x^(2)+7xy+3y^(2)-9x-7y+k=0 represents a pair of lines, then k is equal to

If the equation 2x^(2)-3xy+y^(2)-kx+5y+6=0 represents a pair of line, then k=

If the equation x^(2)+3xy+2y^(2)+x-y+k=0 represents a pair of line, then k=

If the equation kx^(2)-y^(2)+4x-y=0 represents a pair of line, then k=

If k x^(2)-y^(2)+2 x-y=0 represents a pair of lines, then k=

If the equation 2x^(2)+4xy-2y^(2)+4x+8y+k=0 represents a pair of line, then k=

If the equation 2x^2+5xy+3y^2+6x+7y+=0 represents a pair of lines, then the equation of pair of lines parallel to then and passing through the point (0,1) is