Answer:
I believe it's the 3rd awnser
Answer:In geometry, the parallel postulate, also called Euclid's fifth postulate because it is the fifth postulate in Euclid's Elements, is a distinctive axiom in Euclidean geometry. It states that, in two-dimensional geometry
I'm assuming you mean triangle angles?
If so, all angles add up to 180 so combine them and set them equal to 180.
51+82+5x+2=180
135+5x=180
5x=45
x=9
Expand the brackets first
5(wx-v) = 9(x + v)
5wx - 5v = 9x + 9v
Get all x's on one side and everything on on the other side
9x - 5wx = 9v + 5v
factorise out the x
x(9-5w) = 14v
then divide by 9-5w
x = 14v/(9-5w)