Vector Addition? Which Vectors Do I Draw and Where?

[Stanc]

Homework Statement

Vectors a and b have magnitudes 2 and 3. The angle between them is 50 degrees. Determine 5a - 2b and determine its magnitude and direction

Homework Equations

Cosine Law and Sine Law

The Attempt at a Solution

I can solve for the magnitude using the cos law and obtain an answer of 7.67 which is correct, however the direction and angle looks as if which vector i draw and where I draw it Heres a picture (The magnitudes I have just labelled as 10 which is 5a and 6 for 2b) :

Which drawing should I use, because It results in me getting different angles and direction

 

[tms]

The most straightforward approach would be to pick one vector as the x axis, then break the other into its component, and add them that way.