Question

please answer ASSUMING THAT STRAIGHT LINE WORK AS A PLANE MIRROR FOR A POINT FIND THE IMAGE OF POINT (1,2) IN THE LINE x-3y+4=0.

Answer 1

Let x=1
Therefore 1-3y+4=0
1-4+3y=0
-3+3y=0
3y=3
y=3/3
y=1
and substitute the of y in equation