If the equation $ax^{2} + hxy + by^{2} = 0$ represents a pair of coincident lines,then

The joint equation of the straight lines $x + y = 1$ and $x - y = 4$ is

If $ax^2-34xy-5y^2+2x+26y-5=0$ represents a pair of straight lines,then the value of $a$ is

If one of the lines of the pair $ax^{2}+2hxy+by^{2}=0$ bisects the angle between the positive direction of the axes,then $a, b,$ and $h$ satisfy the relation:

The combined equation of two lines $L$ and $L_1$ is $2x^2+axy+3y^2=0$ and the combined equation of two lines $L$ and $L_2$ is $2x^2+bxy-3y^2=0$. If $L_1$ and $L_2$ are perpendicular,then $a^2+b^2=$

The combined equation of the lines passing through the point $(3,4)$ and each making an angle $45^{\circ}$ with the line $x+y+1=0$ is