For What Value Of $x$ Are $5 \vec{i}-6 \vec{j}+2 \vec{k}$ And $x \vec{i}-2 \vec{j}+2 \vec{k}$

For what value of $x$ are $5 \vec{i}-6 \vec{j}+2 \vec{k}$ and $x \vec{i}-2 \vec{j}+2 \vec{k}$ perpendicular?