Answer:
1. The angles of a triangle added up all together is 180. So, we can solve a as an equation!
36+57+a=180.
From this, we can figure out a:
a=87
2. The same goes for this one, just a bit different. We write our equation like this:
3x+90=180
we solve this:
3x=90
we divide both sides by 3 and get:
x=30