The equation of a line is $3x+4y-7=0$. Find the equation of a line perpendicular to the given line and passing through the intersection of the lines $x-y+2=0$ and $3x+y-10=0$.

Given equation of line ${\mathrm{L}}_1$ is $\mathrm{y}=4$ 

Write the slope of line ${\mathrm{L}}_2$, if ${\mathrm{L}}_2$ is the bisector of angle $\mathrm{O}$.

Given equation of line ${\mathrm{L}}_1$ is $\mathrm{y}=4$

If ${\mathrm{L}}_2$ is the bisector of angle $\mathrm{O}$.

Write the co-ordinates of point $\mathrm{P}$. 

Given equation of line ${\mathrm{L}}_1$ is $\mathrm{y}=4$

If ${\mathrm{L}}_2$ is the bisector of angle $\mathrm{O}$.

Find the equation of ${\mathrm{L}}_2$.

Find equation of $\mathrm{AB}$. 

Find equation of $\mathrm{CD}$.