#### promitheus

##### New member

- Joined
- Aug 19, 2017

- Messages
- 18

Q: Find parametric equations and equation in vector form for the line y= 3x-1

My attempt:

Substituting x=1 and x=0 in the above equation we get two points P(1,2) and Q(0,-1) on the line

Direction vector

**d= q-p =**[-1,-3]

Vector equation is of the form

**x= p + d**t

So

**x =**[1,2] + t [-1,-3] <-----------Question: Could I factor out the -1 as the scalar quantity t covers -1?

Parametric eqn:

x= 1 + t

y= 2 + 3t

The textbook has the co-ordinates of point P and Q switched around.

Am I correct in thinking that the points are arbitrary and should not affect the equations?

Hope this makes sense.

Thanks!