Questions in pair-st-lines

Select	Question
	The equation of the lines represented by the equation ${{x}^{2}}-5xy+6{{y}^{2}}=0$ are
	If the equation $a{{x}^{2}}+b{{y}^{2}}+cx+cy=0$ represents a pair of straight lines, then
	The equations of the lines represented by the equation $a{{x}^{2}}+(a+b)xy+b{{y}^{2}}+x+y=0$ are
	The equation ${{x}^{2}}-7xy+12{{y}^{2}}=0$ represents
	The equation ${{y}^{2}}-{{x}^{2}}+2x-1=0$ represents
	If the equation $\lambda {{x}^{2}}+2{{y}^{2}}-5xy+5x-7y+3=0$ represents two straight lines, then the value of $\lambda$ will be
	The equation of one of the line represented by the equation ${{x}^{2}}+2xy\cot \theta -{{y}^{2}}=0$, is
	The equation of one of the line represented by the equation $pq({{x}^{2}}-{{y}^{2}})+({{p}^{2}}-{{q}^{2}})xy=0$, is
	The pair of straight lines passes through the point (1, 2) and perpendicular to the pair of straight lines $3{{x}^{2}}-8xy+5{{y}^{2}}=0$, is
	If in general quadratic equation $f(x,\,y)=0$, $\Delta =0$ and ${{h}^{2}}=ab$, then the equation represents