What is the value of a in the equation 3a+b=54, when b =9?

What is the 12th term of b(n)=-4-2(n-1)

A. 90 degrees b. 45 degrees c. 30 degrees d. 120 degrees

A3-dimensional figure has a square base and 4 lateral faces that meet at a point. explain the difference between the cross sections when a slice is made perpendicular to the base through the vertex, and when a slice is made perpendicular to the base and not through the vertex