Answer:
9(6c - d)
Step-by-step explanation:

Answer:
--- Vertex
--- Axis of symmetry
Step-by-step explanation:
Given

Solving (a): The vertex
For an equation written in

The vertex is:

By comparison:
and 

So, the vertex is:

Solving (b): The axis of symmetry
For an equation written in

The axis of symmetry is:
x = h
In (a):

So:

-2bc=12-3ab
c=(3ab-12)/(2b)
3(x + 1) - 2x = -6 |use distributive property: a(b + c) = ab + ac
3x + 3 - 2x = -6
x + 3 = -6 |subtract 3 from both sides
x = -9