$-2 \times x\times y\times z$.
Work Step by Step
We know that we need an expression with x, y, and z in it. To make it simpler, we will multiply the three numbers together. Because $x\times y\times z$ equals -6 right now, we must multiply -6 by a number to get 12. We know that -6 times -2 is 12, so we get the expression: $-2 \times x\times y\times z$.