JEE Main 2026 · 6 Apr · Shift 1, Mathematics question 23

If $\vec a=\hat i+\hat j+\hat k$, $\vec b=\hat j-\hat k$ and $\vec c$ be three vectors such that $\vec a\times\vec c=\vec b$ and $\vec a\cdot\vec c=3$, then $\vec c\cdot\left(\vec a-2\vec b\right)$ is equal to ________.