Hi
Use Euler's formula for this for a 3D figure. F + V = E + 2, where F is the number of faces, V is the number of vertices, E is the number of edges, +2! You have enough info to fill in the formula to find that the number of vertices is 6.
Hoped I Helped
A: 450. 1,350-1,200=150 x 3=450.
B: I'm not sure how to make a slope intercept graph... :(