For #1 it's going to be proper because it's pretty specific, and for number two it's going to be all common because it's not citing anything specific.
I made a risky challenge because I wanted to make a joke. I handled it by just taking it truthfully and just say that it was a joke.
Just pick a number greater than 1 and that would be for P
Okay, you now a triangle has 180º degrees and to add to 180º, you have to add all the numbers you have like this:
2x+x+90 (the box is 90º)=180º; add like terms like 2x+x
3x+90=180; cancel 90 by subtracting it and also subtract 90 from 180
3x=90;divide 3 to isolate x and also divide 90/3
x=30 :)
