
Step-by-step explanation:

Answer:
3x +45°=180° (due to straight angle)
or, 3x= 180°-45°
or,3x= 135°
or,X=135°/3
X =45°.ans
Answer: 
Step-by-step explanation:

The expression is 2 x3 + 7 =13
(Correct me if I’m wrong in comments)
Answer: 80
Reasoning: A polyhedron can have 30 edges. If this polyhedron has 120 it has 4 times the “other” one. If it has 30 edges it will have 20 vertices, meaning 20*4=80 vertices