Question

The points on the line x+y=4 lying at a unit distance from the line 4x+3y-10=0 are

Answer 1

x+y=4.............1

4x+3y=10.............2

multiple equation 1 by 3

3x+3y=12...............3

subtract equation 2 and 3

4x+3y=10

- 3x+3y=12

- -

-------------

×=-2

substitute in equation 1

x+y=4

-2+y=4

y=4+2

y=6

The points are (x,y)=(-2,6)