2ax+6bx+ay+3by-az-3bz

The given expression is 2ax + 6bx + ay + 3by - az - 3bz. This is an algebraic expression with several terms involving variables a, b, and x, y, z.

To simplify or combine like terms in this expression, we need to group terms that have the same variables and exponents. Let's rearrange the terms:

2ax + 6bx + ay + 3by - az - 3bz

Rearranging the terms alphabetically by variables gives us:

2ax + 6bx + ay - az + 3by - 3bz

Now, let's combine the terms that have the same variables:

(2a - a)xy + (6b - 3b)xy - (a - 3b)z

Simplifying further, we get:

a(xy) + 3b(xy) - (a - 3b)z

Factoring out the common factors:

(axy + 3bxy) - (a - 3b)z

Combining like terms one last time, we simplify to:

(4axy) - (a - 3b)z

Therefore, the simplified expression is 4axy - (a - 3b)z.