Question

A solid has 14 faces and 12 vertices. How many edges does the solid have

Answer 1

Number of faces + (Number of vertices - Number of edges) = 2
14 + (12 - x) = 2
12 - x = 2 - 14
12 - x = - 12
- x = -12 - 12
-x = - 24
x = 24

There would be 24 edges.
(Credit to Taskmasters who answered a question similar previously)