Problem:
The lines L and K are symmetric to each other with respect to the line y=x. If the equation of line L is y=ax+b with aî€ =0 and bî€ =0, then the equation of K is y=
Answer Choices:
A. a1​x+b
B. −a1​x+b
C. −a1​x−ab​
D. a1​x+ab​
E. a1​x−ab​
Solution:
If (p,q) is a point on line L, then by symmetry ( q,p ) must be a point on K. Therefore, the points on K satisfy
x=ay+b.
Solving for y yields
y=ax​−ab​.