Questions in pair-st-lines

Select	Question
	If $6{{x}^{2}}+11xy-10{{y}^{2}}+x+31y+k=0$ represents a pair of straight lines, then $k=$
	If $4ab=3{{h}^{2}}$, then the ratio of slopes of the lines represented by the equation $a{{x}^{2}}+2hxy+b{{y}^{2}}=0$ will be
	The lines represented by the equation $a{{x}^{2}}(b-c)-xy(ab-bc)+c{{y}^{2}}(a-b)=0$ are
	If the equation $a{{x}^{2}}+2hxy+b{{y}^{2}}=0$ represents two lines $y={{m}_{1}}x$ and $y={{m}_{2}}x$, then
	The nature of straight lines represented by the equation $4{{x}^{2}}+12xy+9{{y}^{2}}=0$ is
	The equation of the perpendiculars drawn from the origin to the lines represented by the equation $2{{x}^{2}}-10xy+12{{y}^{2}}+5x-16y-3=0$ is
	Which of the following second degree equation represented a pair of straight lines
	The lines ${{a}^{2}}{{x}^{2}}+bc{{y}^{2}}=a(b+c)xy$ will be coincident, if
	If the equation $2{{x}^{2}}-2hxy+2{{y}^{2}}=0$ represents two coincident straight lines passing through the origin, then $h=$
	If one of the lines represented by the equation $a{{x}^{2}}+2hxy+b{{y}^{2}}=0$ be $y=mx$, then