1.
Given the vectors u⃗=2i^−j^−k^\vec{u} = 2\hat{i} - \hat{j} - \hat{k}, v⃗=i^−j^+2k^\vec{v} = \hat{i} - \hat{j} + 2\hat{k}, w⃗=i^−k^\vec{w} = \hat{i} - \hat{k}. If the volume of the parallelopiped having −cu⃗-c\vec{u}, v⃗\vec{v} and cw⃗c\vec{w} as concurrent edges is 88, then cc can be equal to