Questions in pair-st-lines

Select	Question
	The straight lines joining the origin to the points of intersection of the line $2x+y=1$ and curve $3{{x}^{2}}+4xy-4x+1=0$ include an angle
	The angle between the pair of straight lines ${{x}^{2}}+4{{y}^{2}}-7xy=0$, is
	The angle between the pair of lines given by equation ${{x}^{2}}+2xy-{{y}^{2}}=0$, is
	The angle between the pair of straight lines ${{x}^{2}}-{{y}^{2}}-2y-1=0$, is
	If the angle between the two lines represented by $2{{x}^{2}}+5xy+3{{y}^{2}}+6x+7y+4=0$ is ${{\tan }^{-1}}m$, then $m=$
	Pair of straight lines perpendicular to each other represented by
	If the lines $(p-q){{x}^{2}}+2(p+q)xy+(q-p){{y}^{2}}=0$ are mutually perpendicular, then
	Which of the equation represents the pair of perpendicular straight lines
	The lines represented by the equation ${{x}^{2}}+2\sqrt{3}xy+3{{y}^{2}}-3x-3\sqrt{3}y-4=0$, are
	If two of the three lines represented by the equation $a{{x}^{3}}+b{{x}^{2}}y+cx{{y}^{2}}+d{{y}^{3}}=0$ are perpendicular, then