Question

determine wheather the point is on a line

Answer 1

You would take your point (x,y) and plug those 2 values into whatever the equation for the line is....and if it works out then that point is on the line...

example...

is the point (1,2) on the line y = x + 1 ?

well we put (x,y) (1 in for x) and (2 in for y)

y = x + 1

becomes

2 = 1 + 1

2 = 2

is this correct? of course it is...so this point is on the line

Hope that helps :)