jmc

To expand, we multiply $(3x-6)$ by $x$ and add that product to the product of $(3x-6)$ and $2$. $$\begin{array}{rl}(x+2)(3x-6)& =x\cdot (3x-6)+2\cdot (3x-6)\\ & =(3x^2-6x)+(6x-12)\end{array}$$Combining like terms gives a final answer of $\boxed{3x^2-12}$.