I missed a week of school and I have a quiz tom on properties of triangles can someone give me a little review on it.

For example

Scalane traingle

bottom right side is (x-15)deg

on the left corner there is an suplmentary extension of 150 so you sutract is by 180 and that gives you 30.

But it says solve for x which is the top of the triangle and im not sure how to do it....