Equation of a Straight Line

Q. $L_1$ is a line intersecting $x$ and $y$ axes at $A(a,0)$ and $B(0,b).$ $L_2$ is a line perpendicular to $L_1$ intersecting $x$ and $y$ axes at $C$ and $D$ respectiveley. If the area of the triangle $OCD$ is 4 times the area of triangle $OAB$, then equation of $AD$ is

1. $x+2y=26$
2. $2x+y+2a=0$
3. $x-2y+2b=0$
4. $2x-y-2a=0$

Q.

If the lines $a_{1}x+b_{1}y+c_1=0\text{and}{a}_{2}x+b_{2}y+c_2=0$ cut the coordinates axes in concyclic points, then

1. $a_1{b}_1=a_2{b}_2$
2. $\frac{a_1}{a_2}=\frac{b_1}{b_2}$
3. $a_1+a_2=b_1+b_2$
4. $a_1{a}_2=b_1{b}_2$